Fig 1: Validation of the three candidate differentially expressed proteins, CORO1A, S100A8 and TCIRG1, by western blotting. (A) Representative mass spectra of CORO1A, S100A8 and TCIRG1-derived peptides (AVDAAFTCPGSSQLYVTAGR, GGDDLDPNYVLSSR and AGLALPPPEGR, respectively) isolated from subchondral bone tissues from 3-month old guinea pigs. (B) Protein samples extracted from the subchondral bone tissues of the indicated age groups were subjected to western blotting. There was a continuous increase in the expression of CORO1A and S100A8 in the subchondral bone in both male and female guinea pigs from 1 to 6 months. Following an initial decrease, the abundance of TCIRG1 increased from month 3 to 6 in the female guinea pigs, whereas its expression levels remained relatively stable in the male guinea pigs. ACTB was used as the loading control. ACTB, ß-actin; S100A8, S100 calcium-binding protein A8; CORO1A, coronin 1A; TCIRG1, T-cell immune regulator 1.