Peer Review History

Original SubmissionApril 25, 2020
Decision Letter - Juan J Loor, Editor

PONE-D-20-11941

Implication of gut microbiota in the physiology of rats intermittently exposed to cold and hypobaric hypoxia

PLOS ONE

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PLOS ONE

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Reviewer #1: Yes

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Reviewer #1: Yes

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Reviewer #1: Yes

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Reviewer #1: Yes

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Reviewer #1: Ms “Implication of gut microbiota in the physiology of rats intermittently exposed to cold and hypobaric hypoxia” ,examined the influence of intermittent exposure to cold, hypobaric hypoxia, and their combination to gut microbiota in SD rats. The main findings are that: cold increased brown adipose tissue, Clostridiales subpopulation and the concentration of butyric and isovaleric acids in caecum. Hypobaric hypoxia increased hemoglobin, red and white cell counts and Enterobacteriales, and reduced body and adipose tissues weights and Lactobacilliales. Cold plus hypobaric hypoxia counteracted the hypoxia-induced weight loss as well as the increase in white blood cells, while reducing the Bacteroidetes:Firmicutes ratio and normalizing the populations of Enterobacteriales and Lactobacilliales.

Data is interesting, data analysis and presentation is fine, conclusion is clear. The main problem is that authors only reported the phenotypic changes and lack the mechanism investigation.

I have some comments and suggestions:

1. Rats raised in 22 C temperature seems too low, rats in this ambient temperature facing cold exposure and thus can increase the thermogenesis (such as from brown adipose tissue and other organs) to keep stable body temperature, and/or increase the food consumption. For 4 C exposure, this is the further (or additive effect) low temperature effect.

2.For brown adipose tissue, from which location and how many BAT removed from the body? if showed some data for UCP1 in BAT and non-shivering thermogenesis will be benefit for the conclusion.

3. It is better to do some transplanting experiments, such as transplanting gut microbiota of cold rats to 22C rats, or from hypoxia to normal condition, or the combination.

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Reviewer #1: No

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Revision 1

Dear Editor and Reviewer,

We would like to thank you for your time and effort concerning our manuscript and the constructive criticism we have obtained. We have addressed the concerns raised by the reviewer in our point-by-point answers and done revisions to the manuscript accordingly as indicated in the following answers.

1. Rats raised in 22 C temperature seems too low, rats in this ambient temperature facing cold exposure and thus can increase the thermogenesis (such as from brown adipose tissue and other organs) to keep stable body temperature, and/or increase the food consumption. For 4 C exposure, this is the further (or additive effect) low temperature effect.

Rats were raised at a standard room temperature of 22 ºC, following the guidelines from European Union and the regulations of the Governments of Catalonia and Spain. Concretely, EU commission recommend rodents should be maintained within a temperature range of 20 ºC to 24 ºC, as follow: https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=celex:32007H0526

The rat’s thermo-neutral zone ranges from 27 to 30 ºC (Gordon, Lee, Chen et al 1991), nevertheless the results obtained in the studied groups are referred to the control group, raised at 22 ºC. In this sense, the results obtained from 4 ºC exposure are an additive effect, as the reviewer pointed out. This is now included in the Discussion section (Lines 243-246)

2. For brown adipose tissue, from which location and how many BAT removed from the body? if showed some data for UCP1 in BAT and non-shivering thermogenesis will be benefit for the conclusion.

The brown adipose tissue collected was the whole interscapular BAT from all animals (now indicated in Line 121).

We agree with the reviewer about the interest about UCP1 in BAT and non-shivering thermogenesis in this kind of studies. Unfortunately, we have not the techniques available to analyse that in the present experiment. We will include them in future works.

3. It is better to do some transplanting experiments, such as transplanting gut microbiota of cold rats to 22C rats, or from hypoxia to normal condition, or the combination.

Despite the interest of a transplantation experiment, it is not possible to do it without the pertinent approval from the Ethical Committee for Animal Experimentation. For the present project, we cannot ask for such authorization since faecal transplantation was not included in the aims of the funded project.

Attachments
Attachment
Submitted filename: Ramos-Romero_Response to Reviewers.docx
Decision Letter - François Blachier, Editor

Implication of gut microbiota in the physiology of rats intermittently exposed to cold and hypobaric hypoxia

PONE-D-20-11941R1

Dear Dr. Ramos-Romero,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

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Kind regards,

François Blachier, PhD

Academic Editor

PLOS ONE

Formally Accepted
Acceptance Letter - François Blachier, Editor

PONE-D-20-11941R1

Implication of gut microbiota in the physiology of rats intermittently exposed to cold and hypobaric hypoxia

Dear Dr. Ramos-Romero:

I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department.

If your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org.

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PLOS ONE Editorial Office Staff

on behalf of

Dr. François Blachier

Academic Editor

PLOS ONE

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