Effects of cyclic mechanical stretch on BMP-2 expression in RA and OA fibroblast-like synoviocytes / 医用生物力学

ABSTRACT

Objective To explore the role of mechanical stimulation in synovium under different pathological conditions through studying the effects of cyclic mechanical stretch on the expression of bone morphogenetic protein 2 (BMP-2) in rheumatoid arthritis (RA) and osteoarthritis (OA) fibroblast-like synoviocytes (FLS). Method 6% and 0.5 Hz stretch generated by Flex cell 4000 tension systems was applied on normal, RA and OA FLS of human knee joint source under normal and inflammatory conditions for 2 h or 6 h, respectively. Results Cyclic mechanical stretch of 6%, 0.5 Hz had no significant effects on the expression of BMP-2 in normal, RA and OA FLS at 2 h, while in RA FLS it increased significantly at 6 h. Inflammatory cytokines (IL-1β) didn’t influence normal FLS at 2 h, but made BMP-2 mRNA significantly increased at 6 h. IL-1β increased BMP-2 mRNA of RA FLS significantly both at 2 h and 6 h. IL-1β increased BMP-2 mRNA of OA FLS significantly only at 2 h, but had no significant effect at 6 h. The co-effect of IL-1β and cyclic mechanical stretch induced the ascension of BMP-2 expression significantly in normal and RA FLS at 2 h, and in normal, RA and OA FLS at 6 h. Conclusions Response of BMP-2 mRNA to mechanic stimulation and IL-1β in normal, RA and OA FLS were different. Inflammation may play a more important role than mechanical stimulation in the pathogenesis of RA and OA. Synergetic effect in inflammation and mechanical stimulation were found in OA FLS at 6 h, which reveals that they may co-act in the occurrence and development of OA.