A recap/repeat of the comments made above:
Major comment (Must be addressed):
For animal experiments, approvals from the appropriate ethics committee e.g. Institutional Review Board (IRB) should be provided in the Methods section.
Minor comments (optional):
1. Ideally, all DNA samples (non TE-treated, TE-treated, fixed tisue, non-fixed tissue etc.) should have been run on a single gel, to enable a direct comparison. The panels A, B and C could then be condensed into just one panel. As this might need additional experiments but does not directly impact the conclusions, this is optional.
2. The objective and conclusion of the results could be mentioned in the figure title / legend so that it can be understood without the need to read the results section. This is just a suggestion to the authors and therefore optional.
3. Apart from treatment with TE, what are the other methods for obtaining good quality DNA from fixed tissues? If the authors could provide references and discuss e.g. in futire directions, it would improve the article.