Temporal Profile of Reactive Astrocytes after Ischemic Stroke in Rats
, Lucas Garmo 1,3, Bhairavi Srinageshwar 1,2,3, Marc R. Spencer 4, Robert B. Petersen 1, Gary L. Dunbar 2,3,5,6 and Julien Rossignol 1,2,3,*Round 1
Reviewer 1 Report
This is an important study detailing a timeline of pathological events following an ischemic stroke in a rat model. The methods are solid and the results are strengthened by the use of male and female rats. There are a few suggestions that could improve the manuscript.
MCAo is used a few times before it is defined in section 2.1. Define at first use.
The authors provide the Infarct Volume and GFAP date in Table 2, rendering Figures 3 and 7 unnecessary. If the authors decide to keep the figures, Figure 3 should be a bar graph since the design was cross sectional and not longitudinal.
Because the design was cross sectional and not longitudinal, when comparing groups the authors should refer to values as greater or less than rather than increased or decreased.
It would be good if the authors speculated on the different outcomes in the cortex vs striatum.
In the third paragraph of the discussion, the authors refer to "...the most significant difference shown between Group 2 and Group 3..." Statistically, differences are not more significant or less significant. They are either significant or they are not. Replace "most significant" with "greatest".
If the authors decide to keep Figure 7, the conclusion stated in the final sentence should be more limited to the results of this study. As the authors state, other studies have reported different effects using different stroke parameters.
Author Response
On behalf of all authors, I would like to thank you for considering our manuscript, “Temporal Profile of Reactive Astrocytes After Ischemic Stroke in Rats”, submitted to Neuroglia. We are grateful for the reviewers’ comments and have revised the manuscript to address their concerns. Please find the revised manuscript attached alongside the submission documents, as well as our point-by-point response to the reviewers in the following pages.
We believe this manuscript is of special interest to the audience of Neuroglia, as it elucidates the timeline of astrocyte reactivity following ischemic stroke. At the time of submission, the literature lacked studies that explicitly elucidated the sequence of events, which we believe are crucial for research and development of future treatments and protocols with respect to appropriate timing. As the intent of the current study was specific to the timeline of peak astrocyte reactivity in the ischemic cascade, we believe the dissemination of these findings may inspire future research that focusses on other associated factors as highlighted in the discussion.
We believe that the comments and suggestions made by the reviewers have strengthened our manuscript significantly and would like to thank them for their time. We sincerely hope that you find our revised manuscript to be acceptable for publication in Neuroglia.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Here the authors present data to determine the temporal profile of astrocyte reactivity following ischemic stroke. I find this work and it's presentation in this manuscript to be sound and worthy of publication in its present form.
Author Response
please see attachment
Author Response File: Author Response.pdf
Reviewer 3 Report
The manuscript by Stadler et al explores the GFAP reactivity in the ischemic brain aiming to define the temporal profile of reactive astrogliosis for potential therapeutic interventions. Analysis and methodologies are detailed; however study design and data presentation have several shortcomings. The most critical issue is how the current study differs from a large number of studies showing reactive gliosis in ischemia with a defined timeline is not clear. Also, how the current study enhances our knowledge of glial reactivity, ischemia, and glial-oriented therapeutic targets is obscure.
I have the following major comments:
1. In the abstract, authors need to define astrocytic reactivity followed by stating GFAP overexpression as one of the significant changes. Please see https://pubmed.ncbi.nlm.nih.gov/33589835/.
2. Introduction P2 lines 71-72, the statements appear as if only ischemic brain astrocytes undergo astrogliosis. Please rephrase the statement stating ischemia as one of the pathologies in which astrogliosis occurs.
3. Introduction P2, lines 82-87, authors should add some literature on how emerging A1 and A2 astrocytic types can impact the acute phase of ischemia.
4. In the introduction, authors should add some litterateur on how astrocytic changes in the acute phase are deleterious to neuronal functions and recovery.
5. Introduction the last paragraph, simply determining the timeline of GFAP expression in a different model appears to be a repetition /confirmation of existing literature. Please elaborate on the idea, rationale, and novelty to understand the true nature of the study.
6. Figure 1 b is confusing; it appears that authors added drew an area that is filled with some color. Please draw the only outline. no colors should be filled in the outlined area.
7. Figure 3; authors should also present the representative H&E stained images from all the groups with clear demarcation of the infarct area.
8. In figures 4 and 5, GFAP staining should be complemented by at least one more reactive gliosis marker such as vimentin. How about changes in the astrocytic morphology and proliferation? Does overall astrocytic morphology show similar reversible changes?
9. In the discussion page 11, lines 354-361, authors state that the novelty of the study is in the model that they have used. However, findings are by and large similar in these studies.
10. What is the possible explanation behind the downregulation of GFAP expression at a later time point?
11. Could authors also speculate on the correlation between GFAP expression and infarct volume?
12. How GFAP oriented therapeutic approaches can help with ischemia? Please elaborate on the discussion. Is there any evidence in the literature in which GFAP expression-related manipulations show promising recovery?
Author Response
On behalf of all authors, I would like to thank you for considering our manuscript, “Temporal Profile of Reactive Astrocytes After Ischemic Stroke in Rats”, submitted to Neuroglia. We are grateful for the reviewers’ comments and have revised the manuscript to address their concerns. Please find the revised manuscript attached alongside the submission documents, as well as our point-by-point response to the reviewers in the following pages.
We believe this manuscript is of special interest to the audience of Neuroglia, as it elucidates the timeline of astrocyte reactivity following ischemic stroke. At the time of submission, the literature lacked studies that explicitly elucidated the sequence of events, which we believe are crucial for research and development of future treatments and protocols with respect to appropriate timing. As the intent of the current study was specific to the timeline of peak astrocyte reactivity in the ischemic cascade, we believe the dissemination of these findings may inspire future research that focusses on other associated factors as highlighted in the discussion.
We believe that the comments and suggestions made by the reviewers have strengthened our manuscript significantly and would like to thank them for their time. We sincerely hope that you find our revised manuscript to be acceptable for publication in Neuroglia.
Author Response File: Author Response.pdf
Round 2
Reviewer 3 Report
The authors have addressed my comments. I have no more comments.
