The Effect of the Pyrethroid Pesticide Fenpropathrin on the Cardiac Performance of Zebrafish and the Potential Mechanism of Toxicity

Round 1

Reviewer 1 Report

my suggestions and comments are in the pdf attached, the aim of the study should be properly described, add also newer references, EFSA document also, check how references are cited and how are then they put in the reference list (with numbers)

Comments for author File: Comments.pdf

Author Response

Comments and Suggestions for Authors

my suggestions and comments are in the pdf attached, the aim of the study should be properly described, add also newer references, EFSA document also, check how references are cited and how are then they put in the reference list (with numbers) peer-review-31798803.v1.pdf

The authors thank you for the thorough and constructing review. The author also agree that the aim of the study should properly described in the main manuscript. Thus, some extra paragraph in the introduction section has been added to accommodate this issue.

The author also agree that the reference used in this study was a little bit outdated. Thus, newer references related to the issue has been added in the main manuscript. Furthermore, the citation style also has been updated according to the format provided by MDPI in the revised manuscript.

Reviewer 2 Report

This article reported the effect of fenpropathrin on zebrafish embryos. 

Generally, this article is well written. However, I found some lacks in this paper. 

I think this manuscript acceptable after major revision. 

 

 

Materials and Methods

 

There is inconsistency in acute toxicity test.

In 2.1 animal husbandry and exposure, authors described that 

“After that, the eggs were incubated at28 °C and at 48 hours post fertilization (hpf), the eggs were continuously exposed tofenpropathrin until three days post fertilization (dpf) to observe the potential…”, however, in 2.3 acute toxicity test, authors described that “Eight 24 hpf zebrafish eggs was placed into 48-well plate…”.

Which is the right starting point?

 

2.4 cardiac performance analysis 

Authors refered to previous article, but should describe more deatails. 

For example there are some abbreviations in formula, I could not understand the meanings.

 

Results, Discussion

 

Gata1 mRNA level was dramatically suppressed after exposure, I think it is worth to discuss. Explain and discuss the reason why gata1 is declined. Refer some papers. 

 

I think usually blood flow velocity decrease after embryo stress. However, in this study, fenpropathrin enhanced flow velocity. Please explain why flow rate was increased. 

 

Regarding to cardiac performance, authors should reveal the data of embryo viability. 

Should do the experiments to assess viability (and malformation rate) for example, exposure 1 dpf to 2, 3, 4 dpf. 

 

Author Response

Comments and Suggestions for Authors

This article reported the effect of fenpropathrin on zebrafish embryos. Generally, this article is well written. However, I found some lacks in this paper. I think this manuscript acceptable after major revision. 

Materials and Methods

There is inconsistency in acute toxicity test. In 2.1 animal husbandry and exposure, authors described that “After that, the eggs were incubated at28 °C and at 48 hours post fertilization (hpf), the eggs were continuously exposed tofenpropathrin until three days post fertilization (dpf) to observe the potential…”, however, in 2.3 acute toxicity test, authors described that “Eight 24 hpf zebrafish eggs was placed into 48-well plate…”. Which is the right starting point?

The author thank you for the comment. The animal exposure in the 2.1 section refer to the exposure for the cardiovascular, metabolic rate, and qRT-PCR analysis while the animal exposure in 2.3 section refer to the exposure for LC50 calculation to get the effective concentration for the other analysis by following OECD guideline No. 203. The authors strongly agree that this might cause confusion of the reader, thus the manuscript has been updated in the material and method section to accommodate this issue.  

2.4 cardiac performance analysis

Authors refered to previous article, but should describe more deatails. For example there are some abbreviations in formula, I could not understand the meanings.

The author thanks you for the comment. Some of the abbreviation in the formula was already mentioned in the manuscript, however the author agreed that not all of it were mentioned and could cause some confusion for the reader. Thus, the updated manuscript has already corrected accordingly to reviewer suggestion. Furthermore, the authors also already add more detailed method to calculate the cardiac performance parameter in the updated manuscript.

Results, Discussion

Gata1 mRNA level was dramatically suppressed after exposure, I think it is worth to discuss. Explain and discuss the reason why gata1 is declined. Refer some papers.

The author thanks you for the wonderful suggestion. The authors also strongly agree the mRNA level of gata1 gene was worth mentioned for further discussed. Thus in the revised manuscript, the author already add some previous study that relevant to this issue in the discussion section.

I think usually blood flow velocity decrease after embryo stress. However, in this study, fenpropathrin enhanced flow velocity. Please explain why flow rate was increased.

The author thanks you for the question. It is true that in some case, the stress in cardiovascular system could leads to lower heart rate and stroke volume and resulting decrease blood flow velocity as previously reported in zebrafish exposed to ponatinib which caused cardiac failure [1]. However, as already mentioned in the manuscript, fenpropathrin can bind with several ion channel and cause rapid gating in sodium channel that could potentially increase the heart rate. Furthermore, fenpropathrin could cause cardiomegaly which in this case can increasing the stroke volume and together with some increase the heart rate, it will further increase the cardiac output. It has been well known that the increase in cardiac output will affect the blood pressure thus increasing the blood velocity in the dorsal aorta [2]. Aside from the vasodilation which is a natural response to decrease arterial blood pressure, the significant increase in cardiac output ,which in this study reach double the of the control group, could be already considered the main cause of the significant increase in blood flow velocity [3].

Regarding to cardiac performance, authors should reveal the data of embryo viability. Should do the experiments to assess viability (and malformation rate) for example, exposure 1 dpf to 2, 3, 4 dpf.

The authors thank you for the suggestion. The viability test has been done which is the acute toxicity test based on the OECD guideline No 203. However, the authors didn’t put the zebrafish viability data for 1, 2, and 3 dpf in the manuscript as it was only used to calculate the effective concentration for further fenpropathrin exposure which is based on the LC50 value of 4 dpf. Regarding the malformation rate, author also did not see any noticeable malformation outside of cardiomegaly and frequent spams during the 24 hours of exposure of fenpropahtrin thus we did not mention it in the manuscript. Furthermore, as this manuscript was focused more on potential cardiovascular toxicity of acute exposure to pesticide, the authors did not put any data related to developmental toxicity as it will be out of the scope of the study. However, the author agreed that further study in developmental toxicity effect could be interesting for further study.

1. Lin, H.-C.; Saputra, F.; Audira, G.; Lai, Y.-H.; Roldan, M.J.M.; Alos, H.C.; Aventurado, C.A.; Vasquez, R.D.; Tsai, G.-J.; Lim, K.-H. Investigating Potential Cardiovascular Toxicity of Two Anti-Leukemia Drugs of Asciminib and Ponatinib in Zebrafish Embryos. International Journal of Molecular Sciences 2022, 23, 11711.
2. DeMarco, V.G.; Aroor, A.R.; Sowers, J.R. The pathophysiology of hypertension in patients with obesity. Nature Reviews Endocrinology 2014, 10, 364-376.
3. Ramanlal, R.; Gupta, V. Physiology, vasodilation. In StatPearls [internet], StatPearls Publishing: Treasure Island, 2020.

Round 2

Reviewer 1 Report

few small things to correct, mostly concerning English

Comments for author File: Comments.pdf

Author Response

Comments and Suggestions for Authors:

few small things to correct, mostly concerning English
peer-review-31973247.v1.pdf

Thank you for the review. We already change the updated manuscript according to the reviewer suggestion.

Reviewer 2 Report

The authors commented to reviewer's comment point to point, accurately.

So, I think this manuscript is acceptable in Biology.

Author Response

Comments and Suggestions for Authors

The authors commented to reviewer's comment point to point, accurately.

So, I think this manuscript is acceptable in Biology.

Thank you for the review. We already change the updated manuscript according to the reviewer suggestion.