
==== Front
Braz J Cardiovasc SurgBraz J Cardiovasc SurgrbccvBrazilian Journal of Cardiovascular Surgery0102-76381678-9741Sociedade Brasileira de Cirurgia Cardiovascular 3004391810.21470/1678-9741-2017-0218Original ArticleAcetaminophen Mitigates Myocardial Injury Induced by Lower Extremity
Ischemia-Reperfusion in Rat Model Geldi Onur 1MDKubat Emre 2MDÜnal Celal Selçuk 2MDCanbaz Suat 3MD
1 Department of Cardiovascular Surgery, Zonguldak Atatürk State
Hospital, Zonguldak, Turkey.
2 Department of Cardiovascular Surgery, Karabük Training and
Research Hospital, Karabük, Turkey.
3 Department of Cardiovascular Surgery, Trakya University Faculty of
Medicine, Edirne, Turkey.Correspondence Address: Emre Kubat, Department of Cardiovascular
Surgery, Karabük Eğitim Ve Araştırma Hastanesi Kalp
Ve Damar Cerrahisi Kliniği Alparslan, Cd. no:1 78600, Şirinevler,
Merkez, Karabük, Turkey. E-mail:
fsmith@example.org 2018 May-Jun 2018 33 3 258 264 30 11 2017 24 1 2018 This is an Open Access article distributed under the terms of the
Creative Commons Attribution License, which permits unrestricted use,
distribution, and reproduction in any medium, provided the original work is
properly cited.Objective
The injury-reducing effect of acetaminophen, an effective analgesic and
antipyretic on ischemia-reperfusion continues to attract great attention.
This study analyzed the protective effect of acetaminophen on myocardial
injury induced by ischemia-reperfusion in an experimental animal model from
lower extremity ischemia-reperfusion.

Methods
Twenty-four Sprague-Dawley female rats were randomized into three groups
(n=8) as (i) control group (only laparotomy), (ii) aortic
ischemia-reperfusion group (60 min of ischemia and 120 min of reperfusion)
and (iii) ischemia-reperfusion + acetaminophen group (15 mg/kg/h intravenous
acetaminophen infusion starting 15 minutes before the end of the ischemic
period and lasting till the end of the reperfusion period). Sternotomy was
performed in all groups at the end of the reperfusion period and the heart
was removed for histopathological examination. The removed hearts were
histopathologically investigated for myocytolysis, polymorphonuclear
leukocyte (PMNL) infiltration, myofibrillar edema and focal hemorrhage.

Results
The results of histopathological examination showed that acetaminophen was
detected to particularly diminish focal hemorrhage and myofibrillar edema in
the ischemia-reperfusion + acetaminophen group (P<0.001,
P=0.011), while there were no effects on myocytolysis
and PMNL infiltration between the groups (P=1.000,
P=0.124).

Conclusion
Acetaminophen is considered to have cardioprotective effect in rats, by
reducing myocardial injury induced by abdominal aortic
ischemia-reperfusion.

Aorta, AbdominalAcetaminophenReperfusion Injury
==== Body
Abbreviations,
acronyms & symbols	
APAP	=
N-acetyl-p-aminophenol	
PMNL	= Polymorphonuclear
leukocyte	
INTRODUCTION
Ischemia is the shortage of oxygen and metabolites needed for continuity of cellular
metabolism, resulting from the restriction of blood supply to tissues. Timely blood
flow to ischemic tissue limits ischemia only to reversible cell damage. Blood
re-flow to the ischemic tissue is important for the prevention of irreversible
tissue damage; however, reperfusion may increase tissue damage caused by ischemia.
This is defined as "ischemia-reperfusion injury" and induces a wide pathologic
spectrum from reversible cell damage to multi-organ
dysfunction[1]. Several studies are ongoing to halt or slow the
effects of ischemia-reperfusion injury with preconditioning or postconditioning,
while there are also molecular studies to reduce or halt the activity of oxygen
radicals[2-4]. Many previous studies have reported the presence of
reactive oxygen radicals resulting from cross-clamping to abdominal aorta, and
myocardial ischemia-reperfusion injury induced by inflammatory response in the
surgical treatment of abdominal aortic aneurysm, which is a common disease in
cardiovascular surgery[4-6].

Increase in cardiac morbidity and mortality and, in turn, cardioprotective
approaches, have been subject to many studies to date. Therapeutic studies
particularly aimed at the reduction and prevention of cardiac ischemia-reperfusion
injury still continue to be relevant[7-9]. Acetaminophen or N-acetyl-p-aminophenol (APAP),
which is included in the list of essential medicines for the primary health system,
published by the World Health Organization, is commonly used as an analgesic and
antipyretic[10]. APAP has been used in some experimental studies as
a cardioprotective agent during myocardial
ischemia-reperfusion[11-13]. There is no histopathological study in the
literature addressing the cardioprotective role of APAP in cardiac distant organ
ischemia-reperfusion injury induced by lower extremity ischemia. In this light, the
present study was aimed to make histopathological examination of whether
acetaminophen, which has well-defined analgesic and antipyretic effects and which is
currently addressed by laboratory and pre-clinical studies for its cardioprotective
effects, reduced the myocardial ischemia-reperfusion injury induced by lower
extremity ischemia induced by cross-clamping to the abdominal aorta.

METHODS
Animals and Experimental Groups
This study was conducted after receiving approval (Protocol No:
TÜHDYEK-2011/70 and Decision No: 2011.09.04) of the Trakya University Animal
Experiments Local Ethics Committee. Experimental animals were obtained from the
Experimental Animals Unit of the Faculty of Medicine, Trakya University. Twenty-four
female Sprague-Dawley rats approximately 3-5 months old and weighing 190-250 grams
were randomized in equal numbers (n=8) into the control group, the
ischemia-reperfusion (I/R) group and the ischemia-reperfusion + acetaminophen
(I/R+A) group. Rats were kept in rooms automatically illuminated for 12 hours and
darkened for the subsequent 12 hours, heated at 20-22ºC and moisturized by 40-45%
during the whole experiment. During this period, all rats were kept in transparent
cages and fed with standard rat food, and tap water.

The rats were randomized into three groups (n=8) as (i) control group (only
laparotomy), (ii) aortic ischemia-reperfusion group (60 min of ischemia and 120 min
of reperfusion), and (iii) ischemia-reperfusion + acetaminophen group (15 mg/kg/h
intravenous acetaminophen infusion starting 15 minutes before the end of the
ischemic period and lasting till the end of the reperfusion period). In a study,
Kiris et al.[4] found that cardiac free oxygen radicals production,
lipid peroxidation, and neutrophil activation significantly increased after 30 min
ischemia and 60 min reperfusion in rats undergoing cross-clamping to the abdominal
aorta. Therefore, in our study, we aimed to perform a histopathological examination
after applying myocardial ischemia-reperfusion injury through 60 min ischemia and
120 min reperfusion in a rat model.

Surgical Technique
All study rats were weighted before the procedures and their weights were recorded.
After eight hours of fasting, ketamine hydrochloride 40 mg/kg (Ketalar® 50
mg/ml flacon, Pfizer) + xylazine hydrochloride 5 mg/kg (Rompun® 23.32 mg/ml,
50 ml flacon, Bayer) were administered intramuscularly under anesthesia.

An additional dose of ketamine hydrochloride was planned to be administered if
required during the experiment. An additional dose of ketamine hydrochloride was
administered to ensure spontaneous respiration of rats during the whole procedure.
Rats were laid on the table in the supine position under a heating lamp. Samples
were cannulated in the tail vein, using a yellow cannula. After the skin of all rats
be prepared aseptically, laparotomy was performed through the midline just under the
xiphoid process up to 0.5 cm above the pubis. The intestines were shifted to the
right using a wet cloth after the laparotomy. The infrarenal abdominal aorta was
explored via blunt dissection. All rats were administered heparin (100 unit/kg)
(Nevparin® 25000 IU 5 ml flacon, Mustafa Nevzat) as an anticoagulant. 10
ml/kg 0.9% NaCl was administered from the tail vein for fluid resuscitation during
the whole experiment. Infusion was performed using the Braun® Perfusor.

Ischemia-Reperfusion (I/R) Group
An atraumatic microvascular clamp (Novaclip® 12 mm Angle) was inserted in
the infrarenal abdominal aorta. After clamping, approximately 5 ml of warm
physiological saline solution was administered to the peritoneal cavity. The
abdomen was closed by three silk sutures to prevent fluid loss. Following 60 min
ischemia, the atraumatic microvascular clamp was removed from the infrarenal
abdominal aorta and a 120 min of reperfusion period was introduced. Aortic
ischemia was followed by pulsation loss after the clamping procedure and
reperfusion by aorta pulsation after clamp removal. After these procedures, the
rats were sacrificed and their hearts removed.

Ischemia-Reperfusion + Acetaminophen (I/R+A) Group
In addition to the procedures performed on the rats in the ischemia-reperfusion
group, rats in this group were started on infusion with 15 mg/kg/min
acetaminophen (Perfalgan 1000 mg/100 ml flacon, Bristol-Myers Squibb) 15 minutes
before the aortic clamp was removed, with the infusion lasting till the end of
the reperfusion period. Infusion was performed through the tail vein using
Braun® Perfusor. At the end of the procedures, the rats were sacrificed
and their hearts removed.

Control Group
No clamping was performed in the aorta. 5 ml of warm, 0.9% NaCl was injected in
the abdomen which was then closed by three silk sutures to prevent fluid loss.
The rats were kept under this condition for 180 minutes, the time equivalent to
60 min of ischemia plus 120 min of reperfusion performed in the other two
groups. The rats were then sacrificed and their hearts removed.

Histopathological Examination
Sternotomy was performed in all groups at the end of the reperfusion period, and the
heart was removed for histopathological examination. The tissues were fixed in 10%
neutral-buffered formalin (Carlo Erba Reagents) and embedded in paraffin wax.
Ten-micrometer - thick serial sections were obtained and stained with hematoxylin
and eosin (Sigma Aldrich Co.) for histological evaluation. The specimens of the test
and control groups were examined and photographed in the light microscope.

There is no standard histopathological scoring system in the literature to assess
distal end-organ injury for I/R related myocardium. Following aortic cross-clamping,
free oxygen radicals in the ischemic lower extremity during reperfusion, complement
activation, and neutrophil chemotaxis are the main components of distal end-organ
ischemia-reperfusion injury[5,14]. The main target of all these components is the
endothelial barrier in the coronary microvascular region. An intraendothelial gap is
created due to endothelial injury and myocardial edema,
eventually[15,16]. With endothelial injury, the chemotaxis of
polymorphonuclear leukocyte (PMNL) infiltration occurs[5,14]. In addition,
activation of the complement system enhances tissue edema, directly leading to
cardiomyocyte lysis[5,17]. Complete injury of the endothelium in the coronary
microvascular region results in focal hemorrhages. Thus, the removed hearts were
histopathologically investigated for myocytolysis, polymorphonuclear leukocyte
infiltration, myofibrillar edema and focal hemorrhage.

Statistical Analysis
Statistical analysis was performed using the PASW version 19.0 (SPSS Inc., Chicago,
IL, USA) of the Department of Biostatistics, Faculty of Medicine of Trakya
University (License No=10240642). Data were expressed in median (min-max) values or
number and percentage. The Kruskal-Wallis test was used for intergroup data
comparisons. The Bonferroni-corrected Mann-Whitney U test was used to detect groups
which recorded a difference. Statistical significance was set at
P<0.0167 for the Bonferroni-corrected Mann-Whitney U test. A
P value of less than 0.05 was considered statistically
significant.

RESULTS
Histopathological Examination
At the cellular level, no myocytolytic appearance was observed in all groups.
However, only two samples in the I/R group (25%) were observed to develop light PMNL
infiltration. Myofibrillar edema and focal hemorrhage were detected at a mild and
moderate level. Data pertaining to microscopic examination of heart tissue sections
of the test groups were compared using Kruskal-Wallis test. Comparison of the three
groups produced no statistically significant difference in terms of myocytolysis
(P=1.000) and PMNL infiltration (P=0.124),
whereas there was a statistically significant difference with regards to
myofibrillar edema (P=0.011) and focal hemorrhage
(P<0.001) scores of the groups.

Histopathologic scoring was rated as +1: no change; +2: light injury; +3: moderate
injury; +4: diffuse injury. Results for all the groups are shown in Table 1.

Table 1 The histopathological results of all test groups and the control group.

 	Myocytolysis	PMNL infiltration	Myofibrillar edema	Focal hemorrhage	
C-1	1	1	1	1	
C-2	1	1	1	1	
C-3	1	1	1	1	
C-4	1	1	1	1	
C-5	1	1	1	1	
C-6	1	1	1	1	
C-7	1	1	1	1	
C-8	1	1	1	1	
I/R -1	1	2	1	2	
I/R -2	1	2	2	2	
I/R -3	1	1	1	2	
I/R -4	1	1	2	2	
I/R -5	1	1	2	3	
I/R -6	1	1	2	2	
I/R -7	1	1	2	2	
I/R -8	1	1	1	3	
I/R +A-1	1	1	1	1	
I/R +A -2	1	1	1	1	
I/R +A -3	1	1	1	1	
I/R +A -4	1	1	1	1	
I/R +A -5	1	1	2	2	
I/R +A -6	1	1	1	1	
I/R +A -7	1	1	1	1	
I/R +A -8	1	1	1	1	
C=control; I/R=ischemia-reperfusion; I/R+A=ischemia-reperfusion +
Acetaminophen; PMNL=polymorphonuclear leukocyte Histopathologic scoring
was rated as +1 = no change; +2 = light injury; +3 = moderate injury; +4
= diffuse injury.

In the control group, histology of the myocardium was found to be normal and there
were no changes in the myofibrillar appearance. However, myofibrillar swelling and
thick focal hemorrhage were observed in the I/R group, and mild myofibrillar
swelling in the I/R+A group (Figure 1).


Fig. 1 Acetaminophen attenuates the morphological changes associated with aortic
I/R-induced myocardial injury. %" (A) In the control group, the normal
appearance of cardiac myofibrillar. (B) In the aortic I/R group, changes
in the myofibrillar swelling and thick focal hemorrhage. Erythrocytes
are seen as evidence of an intense hemorrhage (black arrows) (C) In the
aortic I/R + acetaminophen group, there is mild myofibrillar swelling
and focal hemorrhage (blood vessels have a normal appearance) (black
arrows). Heart sections are stained by hematoxylin and eosin, and
examined by a light microscope. Magnification: original ×200;
scale bar: 300 µm.




Data pertaining to microscopic examination of heart tissue sections of the study
groups were compared using the Kruskal-Wallis test. Comparison of the three groups
demonstrated no statistically significant difference in terms of myocytolysis
(P=1.000) and polymorphonuclear leukocyte infiltration
(P=0.124), whereas myofibrillar edema
(P=0.011) and focal hemorrhage (P<0.001) scores
of the groups differed on a statistically significant level.

Group-related distributions of histopathological scores of myofibrillar edema and
focal hemorrhage, which were detected using the Kruskal-Wallis test, revealed
statistically significant differences between the study groups.

The Bonferroni-corrected Mann-Whitney U test was used to make statistical analysis of
pair comparisons between the study groups. Statistical significance was set at
P<0.0167. Myocytolysis and PMNL infiltration were not
considered in the pair group comparisons since they were not found in heart tissue
sections, and the Kruskal-Wallis test revealed no statistically significant
difference.

Comparison of the control and I/R groups using Bonferroni-corrected Mann-Whitney U
test revealed a statistically significant difference between the focal hemorrhage
(P<0.001) and myofibrillar edema (P=0.009)
scores of the two groups.

Comparison of the I/R and I/R + A groups using Bonferroni-corrected Mann-Whitney U
test revealed a statistically significant difference between the focal hemorrhage
(P=0.007) scores, while the difference between the same two
groups in terms of myofibrillar edema (P=0.046) was found to be
statistically insignificant (Table 2).

Table 2 Comparison of the groups regarding myofibrillar edema and focal
hemorrhage.

 	Myofibrillar edema	Focal hemorrhage	
Control - I/R	P=0.009*	P<0.001*	
Control - I/R +A	P=0.317	P=0.063	
I/R - I/R +A	P=0.046	P=0.007*	
Bonferroni-corrected Mann-Whitney U test,

* P<0.0167.

I/R=Ischemia-Reperfusion; I/R+A=Ischemia-Reperfusion +Acetaminophen

DISCUSSION
Results of the present study demonstrate that, acetaminophen can reduce myocardial
injury in rats, induced by the I/R which is caused by abdominal aortic
cross-clamping. Histopathological examinations showed that the acetaminophen
administered group suffered less from focal hemorrhage and myofibrillar edema
induced by I/R injury in rats, which supports the suggestion of this study. No
statistically significant difference was detected between the two groups in terms of
myofibrillar edema; however, myofibrillar edema was observed to be suffered less by
the acetaminophen + I/R group.

Aortic cross-clamping inserted during abdominal aortic aneurysm operation, induces
ischemia in the lower extremity. Reperfusion of the ischemic leg with oxygenized
blood results in the formation of toxic oxygen metabolites, leukocyte activation,
cytokine release and activation of the complement cascade[17]. I/R injury is known
to develop in organs such as the lungs, liver and kidney due to oxidative stress and
inflammatory response caused by high amount of reactive oxygen products produced by
lower extremity reperfusion after the removal of
cross-clamping[5,14]. Hydrogen peroxide, hydroxyl and superoxide
radicals, the main reactive oxygen products, are shown to result in peroxidation in
membrane phospholipids of myocardial tissues cells[4]. In addition, I/R injury
is suggested to increase by remote organ infiltration of activated neutrophils due
to aortic I/R and the myeloperoxidase enzyme released by them[4,18,19]. Moreover, released
cytokines, particularly tumor necrosis factor-, induce leukocyte activation and also
damage capillary continuity[17]. Formation of membrane attack complex, the
final product of the complement cascade due to activation of the complement cascade,
contributes to damage the integrity of the cell membrane. C3a and C5a, which are
products of this cascade and known as anaphylatoxins, increase leukocyte
chemotaxis[17]. As understood, distant organ I/R injury is not a
single reaction, but rather a complex process with intracellular and extracellular
pathophysiologic changes. Histological changes in the heart, resulting from I/R, can
be seen via the light microscope[19]. Variables such as myofibrillar edema and focal
hemorrhage detected under the light microscope were recorded in the I/R group, but
not in the control group, which is suggested to be an indicator of distant organ I/R
injury in the heart due to abdominal aorta operation.

When a radical catcher is used to decrease reperfusion injury, considering the fact
that free radicals rapidly develop within a few minutes after reperfusion, the
catcher should be used just before the ischemic period starts or 15 minutes before
reperfusion since it has no preventive effect if used after
reperfusion[20]. As a result, in the scope of the present study,
APAP infusion started 15 minutes before aortic cross-clamping removal.

There are discussions on the mechanism of action of APAP, one of the most popular and
common drugs used in the treatment of pain and temperature. The drug continues to be
a mystery of pharmacology due to its unknown therapeutic
effects[21]. There are experimental studies showing the
possible effects of APAP on reduction of ischemia-reperfusion
injury[11-13,22-30]. Different studies offer different mechanisms in
explaining the effect of APAP. An experimental study by Hadzimichalis et
al.[22]
showed that one of the main mechanisms of I/Rinjury is the opening of mitochondrial
permeability transition pore and the increase in mitochondrial cytochrome release,
and that APAP reduces I/R injury and induces myocyte apoptosis by preventing this
opening and increase. In a study by Baliga et al.[23], acetaminophen was
shown to prevent mitochondrial dysfunction thanks to a similar affect it creates in
I/R in rat brains. In another experimental study, Merrill[24] revealed that APAP,
some phenols of which have antioxidant characteristics, is a phenol compound, and in
turn prevents the release of hydroxyl radicals, which develop in high amounts in the
first minutes of reperfusion, and also reduces peroxide production. In an
experimental study by Rork et al.[25], APAP was shown to have cardioprotective
effects by reducing I/R injury by preventing destruction of matrix
metalloproteinase-2-induced troponin-I activated by peroxynitrite. Many studies were
conducted according to different systems, showing the antioxidant characteristics of
APAP[26-28]. These studies also showed that APAP reduces
in-vivo and in-vitro mitochondria-induced
reactive oxygen amount and suggest that APAP does it by acting like
α-tocopherol and like a direct phenolic radical scavenger. In addition, Nam
et al.[30]
showed in their study that acetaminophen reacts with peroxyl radicals more than with
other phenol compounds used as antioxidant. In their study, Jaques-Robinson et
al.[31]
showed that APAP is a cardioprotective and antiarrhythmic agent against the
oxidative damage induced by hydrogen peroxide in canine heart.

Different studies offer different durations for I/R in the development of myocardial
damage after lower extremity I/R. In a study by Kiris et al.[4] in which the rats were
induced with 30 min ischemia followed by 60 min reperfusion, malonyldialdehyde,
catalase, superoxide dismutase levels, and myeloperoxidase activity were found to be
statistically, significantly higher in the aortic I/R group compared to the control
group. In the aforementioned study, the authors found that the heart was
biochemically affected by elevated oxidative stress metabolism biomarkers with 30
min ischemia and 60 min reperfusion[4]. In their study where 120 minutes of ischemia
were followed by 120 minutes of reperfusion, Narin et al.[19] found statistically
significant higher malonyldialdehyde, catalase, and superoxide dismutase levels in
the aortic I/R group compared to the control group. In the histopathological
examination, myocardial disorganization, myocardial swelling, and myofiber
eosinophilia were examined and all these variables were found to be statistically,
significantly higher in the ischemia-reperfusion group. However, Koçarslan et
al.[7]
performed 45 min ischemia and 60 min reperfusion and found no significant difference
in the I/R injury using cardiac biochemical or histopathological parameters. In an
experimental study, Aydin et al.[8] performed 60 min ischemia and 120 min
reperfusion, as in our study. Similar to Koçarslan et
al.[7]'s study, the authors examined interstitial edema,
inflammatory cellular infiltration, and coagulation necrosis, and they were able to
find a significant difference only in the myofibrillar swelling in the I/R group.
Koçarslan et al.[7] showed that, although the biomarkers of the
oxidative stress metabolism increased during I/R, there was no histopathological
sign indicating that 45 min ischemia does not lead to cardiac injury as assessed by
light microscopy. These findings suggest that 60 min ischemia at least should be
applied for distal end-organ injury in the lower extremity I/R model in rats, as in
our study. Although PMNL is a component for I/R injury, it did not lead to a
statistically significant difference in cardiac infiltration in our study and
previous studies. Although we found a significant difference in myofibrillar
swelling and focal hemorrhage between the control and ischemia-reperfusion groups,
we observed no myocytolysis and PMNL infiltration, indicating no severe reaction to
achieve enhanced complement system activation and significant PMNL infiltration in
the I/R model (Table 2). Therefore, we
suggest longer I/R duration to histopathologically examine these four parameters
under light microscopy.

The present study suggests that APAP reduced focal hemorrhage in the I/R group at a
statistically significant level but had no such effect on myofibrillar edema. The
statistical significance of our study was increased by lowering the statistical
significance down to P<0.0167. As a result of the Bonferroni
correction, the examination of median values shows that myofibrillar edema was
histopathologically higher in the I/R group, although acetaminophen was observed not
to reduce myofibrillar edema at a statistically significant level (Table 2). Authors of the present study suggest
that despite having no statistically significant preventive effect on myofibrillar
edema, acetaminophen has a clinically protective effect.

There are two limitations of the present study. The first limitation is the small
sample size, while the second limitation is that cardiac injury resulting from
ischemia-reperfusion injury and reactive oxygen metabolite activity induced by I/R
were not analyzed using biochemical indicators.

CONCLUSION
In conclusion, acetaminophen is considered to have cardioprotective effects by
reducing myocardial injury induced by abdominal aortic ischemia-reperfusion. Studies
continue to be made to reduce ischemia-reperfusion injury in times when cardiac
morbidity and mortality is on the increase. Future clinical studies should be made
concerning the effect of acetaminophen.

Authors' roles & responsibilities	
OG	Substantial contributions to the
conception or design of the work; the acquisition, analysis, or
interpretation of data for the work; drafting the work or revising
it critically for important intellectual content; agreement to be
accountable for all aspects of the work in ensuring that questions
related to the accuracy or integrity of any part of the work are
appropriately investigated and resolved; final approval of the
version to be published	
EK	Drafting the work or revising it
critically for important intellectual content; agreement to be
accountable for all aspects of the work in ensuring that questions
related to the accuracy or integrity of any part of the work are
appropriately investigated and resolved; final approval of the
version to be published	
CSÜ	Substantial contributions to the
conception or design of the work; the acquisition, analysis, or
interpretation of data for the work; final approval of the version
to be published	
SC	Substantial contributions to the
conception or design of the work; the acquisition, analysis, or
interpretation of data for the work; drafting the work or revising
it critically for important intellectual content; final approval of
the version to be published	
This study was carried out at the Department of Cardiovascular Surgery, Trakya
University Faculty of Medicine, Edirne, Turkey.

No conflict of interest.

No financial support.

No conflict of interest.
==== Refs
REFERENCES
1 Grace PA   Ischaemia-reperfusion injury Br J Surg 1994 81 5 637 647 8044536 
2 Pierce B  Bole I  Patel V  Brown DL   Clinical outcomes of remote ischemic preconditioning prior to
cardiac surgery: a meta-analysis of randomized controlled
trials J Am Heart Assoc 2017 6 2 
3 Santos CHM  Aydos RD  Nogueira Neto E  Miiji LN  Cassino PC  Alves II    Ischemic postconditioning assessment in the liver of rats
undergoing mesenteric ischemia and reperfusion Braz J Cardiovasc Surg 2016 31 4 287 290 27849300 
4 Kiris I  Okutan H  Savas C  Yonden Z  Delibas N   Gadolinium chloride attenuates aortic
occlusion-reperfusion-induced myocardial injury in rats Saudi Med J 2007 28 3 347 352 17334457 
5 Bown MJ  Nicholson ML  Bell PR  Sayers RD   Cytokines and inflammatory pathways in the pathogenesis of
multiple organ failure following abdominal aortic aneurysm
repair Eur J Vasc Endovasc Surg 2001 22 6 485 495 11735196 
6 Grünenfelder J  Inderbitzin D  Zünd G  Avital I  Burkhardt T  Candinas D    Increased susceptibility of the left compared to the right
ventricle to remote ischemia/reperfusion injury in human
C1-inhibitor-overexpressing transgene mice J Invest Surg 2002 15 5 281 286 12396432 
7 Koçarslan A  Koçarslan S  Aydin MS  Gunay Ş  Karahan MA  Taşkın A    Intraperitoneal administration of silymarin protects end organs
from multivisceral ischemia/reperfusion injury in a rat
model Braz J Cardiovasc Surg 2016 31 6 434 439 28076620 
8 Aydin MS  Caliskan A  Kocarslan A  Kocarslan S  Yildiz A  Günay S    Intraperitoneal curcumin decreased lung, renal and heart injury
in abdominal aorta ischemia/reperfusion model in rat Int J Surg 2014 12 6 601 605 24815029 
9 Ding S  Yang Y  Mei J   Protective effects of L-malate against myocardial
ischemia/reperfusion injury in rats Evid Based Complement Alternat Med 2016 2016 3803657 26941825 
10 World Health Organization  "20th WHO essential medicines list and the 6th WHO essential medicines
list for children" Updated in March 2017 Available from: http://www.who.int/medicines/publications/essentialmedicines/en/  
11 Merrill GF  Goldberg E   Antioxidant properties of acetaminophen and
cardioprotection Basic Res Cardiol 2001 96 5 423 430 11605988 
12 Golfetti R  VanDyke K  Rork T  Spiler N  Merrill G   Acetaminophen in the post-ischemia reperfused
myocardium Exp Biol Med Maywood 2002 776-56-2132 1037 
13 Zhu YZ  Chong CL  Chuah SC  Huang SH  Nai HS  Tong HT    Cardioprotective effects of nitroparacetamol and paracetamol in
acute phase of myocardial infarction in experimental rats Am J Physiol Heart Circ Physiol 2006 290 2 H517 H524 16172162 
14 Papaharalambus CA  Griendling KK   Basic mechanisms of oxidative stress and reactive oxygen species
in cardiovascular injury Trends Cardiovasc Med 2007 17 2 48 54 17292046 
15 Garcia-Dorado D  Oliveras J   Myocardial oedema: a preventable cause of reperfusion
injury? Cardiovasc Res 1993 27 9 1555 1563 8287430 
16 Gündüz D  Kasseckert SA  Härtel FV  Aslam M  Abdallah Y  Schäfer M    Accumulation of extracellular ATP protects against acute
reperfusion injury in rat heart endothelial cells Cardiovasc Res 2006 71 4 764 773 16836989 
17 Eliason JL  Wakefield TW   Metabolic consequences of acute limb ischemia and their clinical
implications Semin Vasc Surg 2009 22 1 29 33 19298933 
18 Herbert KJ  Hickey MJ  Lepore DA  Knight KR  Morrison WA  Stewart AG   Effects of the endothelin receptor antagonist bosentan on
ischaemia/ reperfusion injury in rat skeletal muscle Eur J Pharmacol 2001 424 1 59 67 11470261 
19 Narin C  Kiris I  Gülmen S  Toy H  Yilmaz N  Sütcü R   Endothelin receptor blockade with tezosentan ameliorates
myocardial injury induced by abdominal aortic
ischemia-reperfusion Tohoku J Exp Med 2008 216 3 267 276 18987461 
20 Park JL  Lucchesi BR   Mechanisms of myocardial reperfusion injury Ann Thorac Surg 1999 68 5 1905 1912 10585102 
21 Bertolini A  Ferrari A  Ottani A  Guerzoni S  Tacchi R  Leone S   Paracetamol: new vistas of an old drug CNS Drug Rev 2006 12 3-4 250 275 17227290 
22 Hadzimichalis NM  Baliga SS  Golfetti R  Jaques KM  Firestein BL  Merrill GF   Acetaminophen-mediated cardioprotection via inhibition of the
mitochondrial permeability transition pore-induced apoptotic
pathway Am J Physiol Heart Circ Physiol 2007 293 6 H3348 H3355 17921323 
23 Baliga SS  Jaques-Robinson KM  Hadzimichalis NM  Golfetti R  Merrill GF   Acetaminophen reduces mitochondrial dysfunction during early
cerebral postischemic reperfusion in rats Brain Res 2010 1319 142 154 20079345 
24 Merrill GF   Acetaminophen and low-flow myocardial ischemia: efficacy and
antioxidant mechanisms Am J Physiol Heart Circ Physiol 2002 282 4 H1341 H1349 11893570 
25 Rork TH  Hadzimichalis NM  Kappil MA  Merrill GF   Acetaminophen attenuates peroxynitrite-activated matrix
metalloproteinase-2-mediated troponin I cleavage in the isolated guinea pig
myocardium J Mol Cell Cardiol 2006 40 4 553 561 16530785 
26 Orhan H  Sahin G   In vitro effects of NSAIDS and paracetamol on oxidative
stress-related parameters of human erythrocytes Exp Toxicol Pathol 2001 53 2-3 133 140 11484831 
27 Chou TM  Greenspan P   Effect of acetaminophen on the myeloperoxidase-hydrogen
peroxide-nitrite mediated oxidation of LDL Biochim Biophys Acta 2002 1581 1-2 57 63 11960752 
28 Maharaj H  Maharaj DS  Daya S   Acetylsalicylic acid and acetaminophen protect against oxidative
neurotoxicity Metab Brain Dis 2006 21 2-3 189 199 16855872 
29 Shertzer HG  Schneider SN  Kendig EL  Clegg DJ  D'Alessio DA  Genter MB   Acetaminophen normalizes glucose homeostasis in mouse models for
diabetes Biochem Pharmacol 2008 75 6 1402 1410 18237716 
30 Nam TG  Nara SJ  Zagol-Ikapitte I  Cooper T  Valgimigli L  Oates JA    Pyridine and pyrimidine analogs of acetaminophen as inhibitors of
lipid peroxidation and cyclooxygenase and lipoxygenase
catalysis Org Biomol Chem 2009 7 24 5103 5112 20024105 
31 Jaques-Robinson KM  Golfetti R  Baliga SS  Hadzimichalis NM  Merrill GF   Acetaminophen is cardioprotective against H2O2-induced injury in
vivo Exp Biol Med Maywood 2008 776-56-2132 1322


{'source': 'PubMedDataset'}