Figure 3.

Col12a1 KO mice show alterations in muscle fibers organization

(A) Representative images of the whole hindlimb knee joints from P3 and P12 mice after skin removal and of isolated quadriceps muscle from 1-month to 6-month mice. Scale bar, 1mm.

(B) M. quadriceps femoris and M. gastrocnemius were isolated from 6-month-old female mice and their weight (MW) normalized to individual body weight (BW) was quantified (n = 5 samples per group).Unpaired two-tailed Student’s t test, ∗, p < 0.05. Error bars are mean ± SD.

(C) In plane matched 7 μm cryo-cross sections of M. quadriceps femoris and M. gastrocnemius muscle from 6-month-old WT and Col12a1 KO mice (n = 10 samples per group) were stained with hematoxylin (nuclei, purple) and eosin (cytoplasm, pink). Representative images are shown. Scale bar, 100 μm. Black arrows indicate centralized nuclei.

(D) Percentage of myofibers with central nuclei was determined in M. quadriceps femoris and M. gastrocnemius muscles of both WT and Col12a1 KO female mice at the age of 6 months (n = 10 samples per group). The percentage of myofibers with centralized nuclei is given. Unpaired two-tailed Student’s t test, ∗∗∗, p < 0.001. Error bars are mean ± SD.

(E) The percentage of individual WGA+ myofibers with a defined Feret’s diameter was determined in M. quadriceps femoris and M. gastrocnemius muscle in WT and Col12a1 KO female mice at the age of 6 months (n = 10 samples per group). Unpaired two-tailed Student’s t test, ∗, p < 0.05; ∗∗, p < 0.01, ∗∗∗, p < 0.001. Error bars are mean ± SD.