Fig. 4: Impacts of Sod2 conditional knockout on oocyte mitochondrial activity and function.

a Representative image of TMRM staining of mature (MII) oocytes from control (L/L) and Sod2 knockout (L/L, Cre) mice, displaying mitochondrial membrane potential across different ages. b Quantification of TMRM signals from (a). Data were mean ± SEM and were analyzed using unpaired two-tailed Student’s t-test, ***p < 0.001, ****p < 0.0001. c Representative image of western blots for SDHB protein in oocytes from L/L and L/L, Cre mice at various ages, with ACTIN as a loading control. N = 50 MII oocytes per lane, with 3-4 independent experiments. d Densitometric analysis of SDHB levels normalized to ACTIN from (c). Data were mean ± SEM and were analyzed using two-tailed unpaired t-test with Welch’ s correction, *p < 0.05, **p < 0.01. e Representative image of complex II activity in ovarian sections from 3-month-old L/L and L/L, Cre mice, with oocyte boundaries marked. f TEM images of early oocytes in primordial follicles from 2-week-old (upper panel) and 6-month-old (lower panel) L/L and L/L, Cre mice. g Mitochondrial area quantification of (f), presented in violin plots with median and quartiles (dashed black line). Mitochondria counts: L/L_2W = 153, L/L, Cre_2W = 177, L/L_6M = 64, L/L, Cre_6M = 94. Kruskal-Wallis test: *p < 0.05, ***p < 0.001. h Mitochondrial circularity calculation of (f), with values closer to 1 indicating greater circularity. Data presented in violin plots with median and quartiles (dashed black line). Mitochondria counts as in (g). Statistical analysis by Kruskal-Wallis test. i Major axis (longer diameter) measurements of (f), presented as violin plots with medians and quartiles (dashed black line). Mitochondria counts as in (g). Kruskal-Wallis test: ****p < 0.0001. j Minor axis (shorter diameter) measurements of (f), resented as violin plots with medians and quartiles (dashed black line). Mitochondria counts as in (g). Kruskal-Wallis test: *p < 0.05, ***p < 0.001, ****p < 0.0001.