Fig. 5: Effect of lunar gravity on myofiber type in the soleus muscle.

a Immunohistochemical staining for myosin heavy chain using BA-D5 (type I; blue), SC-71 (type IIa; red), and BF-F3 (type IIb; green) antibodies. Unstained myofibers are defined as type IIx (black). Scale bar, 100 μm. b Frequency of each myofiber type in all groups. Data are represented as the mean and SD, and each point represents an individual mouse; n = 9 for GC and n = 3 for all other groups. ^*P < 0.05, ^**P < 0.01, and ^***P < 0.001, as determined using Tukey’s tests. c Actn3 expression in the soleus muscle. d Mb expression in the soleus muscle. Expression values are normalized by transcripts per million (each GC = 1). Data are represented as the mean and SD, and each point represents an individual mouse; n = 3 for each group. ^*P < 0.05, ^**P < 0.01, and ^***P < 0.001 (false discovery rate-corrected), as determined using the edgeR test (c, d). e Gene set enrichment analysis (GSEA) of “Reactome Glycolysis” for each mouse habitat unit (MHU) mission. f GSEA of “Abnormal mitochondria in muscle tissue” for each MHU mission.