OBJECTIVETo observe the effect of naringin of Drynaria Rhizome, a Chinese medical component of Zhuanggu Jianxi Recipe (ZJR) containing serum on caveolin-p38MAPK signal factors (such as caveolin-1, p-p38, p-ATF-2, IL-1β, and TNF-α) in IL-1β induced rabbit degenerated chondrocytes, and further to explore its mechanism for protecting articular cartilages.

METHODSNaringin of Drynaria Rhizome was obtained and analyzed by HPLC-TOF/MS. Four weeks old New Zealand rabbits were killed and their bilateral knee joints were isolated aseptically. CDs were isolated and then cultured in vitro. The second generation of CDs were used for later experiment. The effect of naringin on CDs proliferation was detected by MTT assay. The effect of naringin on the expression of IL-1β-induced collagen II in CDs was detected by immunohistochemical method. The effect of naringin on caveolin-1, p-p38, and p-ATF-2 protein in IL-1β-induced CDs was detected by Western blot. The effect of naringin on mRNA expression of IL-1β and TNF-α in IL-1β-induced CDs was detected by RT-PCR.

RESULTSThe appearance time of naringin in flow graphs of naringin standard solution and ZJR containing serum was 23.5 min, and the molecular weight ranged between 581.0 and 581.5 m/z. Naringin could promote the proliferation of CDs, and inhibit the effect of IL-1β on collagen II in CDs. Compared with the model group, naringin could reduce the expression of caveolin-1, p-p38, p-ATF-2, IL-1β, and TNF-α in IL-1β induced CDs (P < 0.05), which was approximate to the level of the normal group.

CONCLUSIONSNaringin could not only promote the proliferation of CDs, but also protect IL-1β-induced CDs. Its mechanism might be associated with decreasing the expression of caveolin-1, p-p38, and p-ATF-2 proteins, inhibiting caveolin-p38MAPK signal pathway, and further reducing mRNA expression of IL-1β and TNF-α in the downstream of caveolin-p38MAPK signal pathway.