Review for 10.1186/1471-230X-11-127 (2011)

Reviewer's report
Title:Change of nitric oxide synthase neurons in ileal myenteric plexus of rat
severe acute pancreatitis
Version: 1Date:19 April 2011
Reviewer: Annamaria Szabolcs
Reviewer's report:
The manuscript of Zhong Lin et al describes changes in the number and the
phenotype of nNOS-immunoreactive neurons in the myoenteric plexis (MP) of
rats with severe acute pancreatitis (SAP)-associated gastrointestinal dysmotility.
The experiments were carefully designed and executed and the experimental
methods are presented very clearly. The methods used in this study are suitable
for investigation of the questions asked by the authors. The results showed the
presence of gastrointestinal dysmotility in the animals with SAP. However the
interpretation of the confocal images presented by the authors needs further
explanation. The discussion should focus more on the pathophysiological
relevance of the observations and the possible mechanisms behind these
changes. The authors should also discuss the results in comparison to some
recent publications which could be relevant for this topic. For example Zhou et al
(Surgery. 2011 Feb;149(2):262-75) presented the effect of L-ornithine-induced
pancreatitis on the intestinal motility of rats. In this paper acute pancreatitis
reduced the number of nNOS-IR cells in the myoenteric plexus.
Major Compulsory Revisions
The authors provide confocal images of anti-Hu and nNOS staining of the MP of
control animals and rats with SAP. The anti-Hu antibody stained all neuronal
bodies of the MP. Staining was present in the nuclei and also the cytoplasm of
the neurons. In contrast to this the nNOS staining showed only a cytoplasmic
localization of nNOS. According to the interpretation of the results SAP resulted
in the increased ratio of NOS-IR neurons in the MP and also increased the size
and axon diameter of NOS-IR neurons. However the images of the anti-Hu
staining clearly show that the area that showed anti-Hu staining increased in all
neurons. Compared to this change, the increase of the NOS-IR area between the
two groups was not as significant. The authors should provide images where
they overlay the green and red channel to show the distribution of nNOS staining
compared to the anti-Hu staining. DAPI staining for the same images would also
greatly contribute to the results as it would help to distinguish between nuclear
and cytoplasmic localization of the two antibodies. The authors should discuss
these observations in the manuscript and provide a possible explanation for the
observed changes.
Minor Essential Revisions
1,The manuscripts (especially the discussion) should be carefully revised by a
native English speaker.
2,Terminology should be corrected:
Abstract:
-cholangiopancreatography: the term should not be used as it refers to graphic
imaging of the ducts
-pathological score was higher: use pathological damage was more severe
Methods:
-TritonX-100 enhanced penetration of the tissue: enhance penetration of the
antibody
3, Intestinal transit index: Please indicate in the methods section and in Table 3
that the numbers represent % values (trypan blue containing segment length /
total length x100)
4, In Figure 2 and 3 please double check that the magnification rate is correct.
Figure 2 could be 20x rather that 200x.
5, Please provide explanation for the abbreviation CB1 in the discussion. Does it
refer to cannabinoid receptor 1?
6, The font size used in the REFERENCES is not uniform.
Discretionary Revisions
1, Introduction: Although there are some publications about the possible
beneficial effects of laxatives in SAP, most of them are from animal experiments
and evidence for the clinical effect of these drugs in SAP is not strong enough.
Also no reference is listed for this statement.
2, Results: Abdominal X-ray: Niveau formation could be mentioned as a sign for
ileus.
3, In the discussion part consider to include that the endothelial NOS-induced
vasorelaxation can contribute to the development of hypoxia-reperfusion injury
due to generation of oxygen radicals.
4, The discussion is too long. Some parts of it (as the description of the ENS)
were at least partially already discussed in the introduction. I believe that the
description of different diseases associated with gastrointestinal dysmotility or
other neurotransmitters is not really relevant for this paper as. The discussion
should focus more on the explanation of the observations made by the authors
and the literature that is related to the role of nNOS in pancreatitis associated
dysmotility.
A hypothesis explaining the observed changes would add to the value of the
manuscript.
Level of interest: An article whose findings are important to those with closely
related research interests
Quality of written English: Needs some language corrections before being
published
Statistical review: No, the manuscript does not need to be seen by a
statistician.
Declaration of competing interests:
I declare that I have no competing interests.