Fig. 4

Exercise-induced changes in irisin concentration are related to the health of the cartilage, the structure of the subchondral bone, and the extent of muscle atrophy. a Enzyme-linked immunosorbent assay(ELISA) analysis of serum Irisin concentrations in each group. n = 6. * < 0.05. b Correlation analysis between Osteoarthritis Research Society International (OARSI) score and serum Irisin concentration. c Correlation analysis between muscle fiber cross-sectional area (CSA) and serum Irisin concentration. d Correlation analysis between subchondral bone micro-CT parameters and serum Irisin concentration. e Correlation analysis of percentage of Atrogin-1, MuRF-1, PGC-1α and FNDC5 positive area to serum Irisin concentration. f Correlation analysis between mRNA expression of Atrogin-1 as well as MuRF-1 and serum Irisin concentration. n = 18