The results showed that the protein expression of cleaved-caspase-8, cleaved-caspase-9 and cleaved-caspase-3 are significantly higher when IL-1β stimulated hUCMSCs were cocultured with IL-1β stimulated HFLS-RA cells in comparison to HFLS-RA cells co-cultured with hUCMSCs (Fig. 5b,c,e,f,h,i). This evidence concerns the gene CASP8 and rheumatoid arthritis.