Effect of glucocorticoid induced autophagy on senescence in chondrocytes / 中国病理生理杂志

ABSTRACT

AIM:Toexploretheeffectofglucocorticoidonautophagyandsenescenceinthechondrocytes. METHODS:The collagen II in the normal chondrocytes isolated from the SD rats was checked.After stimulation with glu-cocorticoid, LysoTracker Red staining, MDC staining and Western blot were used to detect the level of autophagy in the chondrocytes.The mTOR pathway related molecules were investigated by Western blot.Cell senescence was analyzed by SA-β-gal staining.RESULTS:A dose-dependent increase in the number of autophagic vacuoles was observed in the dexa-methasone-treated chondrocytes, which was demonstrated by the LysoTracker Red and MDC staining.The expression of LC3-II and beclin-1 was increased by dexamethasone, especially in the cells treated with dexamethasone for 4 d.However, P62 expression was decreased.SA-β-gal staining showed that the percentage of cell senescence was increased by dexam-ethasone.Surprisingly, the cell senescence induced by dexamethasone was exacerbated by the autophagic inhibitor 3-MA. CONCLUSION:Autophagy induced by dexamethasone protects chondrocyte from senescence.The mTOR pathway may be involved in the autophagy activation.