Review for 10.1186/s12876-020-01368-y (2020)

Reviewer ’s report  
 
Title: Increased expression of hypoxia inducible factor -1 alpha and vascular endothelial growth 
factor is associated with diabetic gastroparesis .  
 
Version: 0 Date: 18 May 2020  
 
Reviewer's report:  
 
There are some MAJOR and MINOR concerns, which are as follows  
 
1. Methods section, induction of diabetes, the authors say that they injected 48 rats with 
STZ, among which 6 of them did not survive. The rest of the rats were divided into two groups 4 
and 12 weeks study (n=16). The total comes up to 32 + 6 = 40 What happened to the rest of the 
rats?  Need to specify in this section.  
 
2. Methods section, induction of diabetes sub section, pg 4, line 9…." At the end of week 
4 or 12 W, the rats were killed……." Killed is not a right word to be used for publications, need 
to replace it with "euthanized"  
 
3. Did the authors measure body weight regularly during the study period or only 
measured at the end of the study?  
 
4. Methods section, Detection of Pigment Residual Rate in Stomach subsection, pg 6, line 
4, " food or water and killed 30 min later" need to rep lace killed with euthanized.  
 
5. In the histology section the authors mention portion of the gastric biopsy was taken, 
can the authors mention which portion of the gastric tissue was used for histology?  
 
6. Methodology, western blot section, did the authors  pool all the gastric tissues of each 
group or did they processed each specimen separately? What is the number of tissue used 
(n=12)? did they use 100 ml of RIPA lysis buffer for each group?  
 
7. Results section… morphology assessment of diabetic gastric ti ssue section….pg 10, 
line 12…." significantly bigger than hose of control group" needs typo correction.  
 
8. The authors explain that the rats were divided once diabetes were confirmed after 3 
days of STZ injections Fig. 1B, blood glucose levels of the cont rol and STZ induced rats are 
equal?  
 
9. Fig. 1C, gastric acid secretion for diabetic group at 0 time point is missing?  
 
10. Fig. 2A &amp; B, H &amp; E staining is missing for diabetic group at 0 time point?  
 
11. Fig 2D, the labels for the graph are missing?  
 
12. Fig 3A &amp; B, IHC for HIF and VEGF at 0 time point diabetic group is missing?  
 
13. Results section… HIF -1α and VEGF expressed in rat gastric mucosa……was HIF and 
VEGF was significantly expressed higher in both study periods? Need to specify  
 
14. Results secti on… HIF -1α and VEGF expressed in rat gastric mucosa….. both the 
subsections can be combined or title of the subsections needs to be modified?  
 
15. Results section… HIF -1α and VEGF expressed in rat gastric mucosa…pg 11, line 59 
the authors says mRNA expressi ons were significantly higher at all time points (0,4 and 12 wk) 
then what is the control group they are referring? If not why is VEGF and HIF significantly 
higher at 0 time point? Why do the authors even propose or study at different time points?  
 
16. The authors in the results section showed that mRNA expressions were significantly 
higher at all -time points. Fig 4A, doesn't show any mRNA expressions on the gel for 0 time point 
diabetic group, which the authors claim for?  
 
17. In the discussion the authors claim pg 12, line 39 "This study is the first to report the 
increase of HIF -1α and VEGF in the gastric mucosa of diabetic rats" but VEGF (Eur J 
Pharmacol. 2003 Nov 28;481(2 -3):249 -60), and HIF -1α (J Physiol Pharmacol. 2010 
Aug;61(4):429 -36) have already be en published expression of these proteins in diabetic 
stomachs?  
 
18. The authors did not measure nitric acid levels in this diabetic rat model, which is 
correlated with these markers?  
 
19. It requires English editing and check for spelling throughout the man uscript  
 
20. Entire western blot data original blots (complete blots from top to bottom with 
markers) needs to be reviewed for all experimental groups. Recommend to submit as a 
"supplementary" data.  
 
Are the methods appropriate and well described?  
If not, please specify what is required in your comments to th e authors.  
 
No 
 
Does the work include the necessary controls?  
If not, please specify which controls are required in your comments to the authors.  
 
No 
 
Are the conclusions drawn adequately supported by the data shown?  
If not, please explain in your comments to the authors.  
 
No 
Are you able to assess any statistics in the manus cript or would you recommend an 
additional statistical review?  
If an additional statistical review is recommended, please speci fy what aspects require further 
assessment in your comments to the editors.  
 
I recommend additional statistical review  
 
Quality of written English  
Please indicate the quality of language in the manuscript:  
 
Not suitable for publication unless extensively edited  
 
Declaration of competing interests  
Please complete a declaration of competing interests, considering the following questions:  
 
1.  Have you in the past five years received reimbursements, f ees, funding, or salary 
from an organisation that may in any way gain or lose financially from the 
publi cation of this manuscript, either now or in the future?  
 
2.  Do you hold any stocks or shares in an organisation t hat may in any way gain or 
lose financially from the publication of this manuscript, either now or in the 
future?  
 
3.  Do you hold or are you curr ently applying for any patents  relating to the content 
of the manuscript?  
 
4.  Have you received reimbursements, fees, funding, or salary from an organization 
that holds or has applied for patents relating to the content of the manuscript?  
 
5.  Do you have any  other financial competing interests?  
 
6.  Do you have any non -financial competing interests in relation to this paper?  
 
If you can answer no to all of the above, write 'I declare that I have  no competing interests' 
below. If your reply is yes to any, please give details below.  
 
I declare that I have no competing interests  
 
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