Fig. 1: CTRP9 expression is reduced in elderly individuals, and CTRP9 deficiency exacerbates sarcopenia in aging mice.

A Pearson correlation analysis of serum CTRP9 levels in 87 human participants spanning different age groups. B CTRP9 mRNA expression in gastrocnemius muscle from young and aged healthy male C57BL/6J mice (n = 3 per group) analyzed by using the GSE52550 dataset. C Western blot analysis of CTRP9 expression in gastrocnemius muscle from 3-month-old and 23-month-old WT and CTRP9 KO mice; TUBULIN serves as the loading control (n = 5). D Representative photographs of 23-month-old WT and CTRP9KO mice. E Western blot analysis of GLB1, p53, p21, p19 and p16 expression in gastrocnemius muscle from 3-month-old and 23-month-old WT and CTRP9KO mice; GAPDH serves as the loading control (n = 5 for GLB1, p53 and p21; n = 3 for p16 and p19). F Grip strength measurements (N) in WT and CTRP9KO mice across different age groups (n = 8). G Exhaustive running time (min) in WT and CTRP9KO mice across different age groups (n = 8). H Hanging grid test performance (s.g) in WT and CTRP9KO mice across different age groups (n = 8). I Quantitative analysis of individual twitch force (mN) in the gastrocnemius muscle from WT and CTRP9KO mice across different age groups (n = 5). Data are presented as mean ± SEM.