Aim To investigate the potential molecular mechanism of paeoniflorin ( Pae ) in inhibiting PGE2 induced rat fibroblast-like synoviocytes ( FLSs ) hyper-plasy. Methods Rat FLSs were cultured in the presence of prostaglandin E2( PGE2 ) with or without different concentrations of Pae. FLSs proliferations were determined by 3H-TdR incorporation assay. Cyclic adeno-sine monophosphate ( cAMP ) levels in synoviocytes were assessed by radioimmunoassay ( RIA ). The expressions of EP2 and p-arrestin 2 in whole FLSs or on membrane were measured by Western blot or flow cy-tometry. Results Pae significantly inhibited rat FLSproliferation induced by PGE2 via increasing cAMP levels. High levels of total EP2, p-arrestin 2 and membrane p-arrestin 2 expression in FLSs induced by PGE2 were decreased by different concentrations of Pae administration. EP2 was downregulated on FLSs membrane after PGE2 stimulation; however, was restored by Pae in various degrees. Conclusions Our findings suggest that Pae inhibits rat FLSs proliferation induced by PGE2 via arresting EP2 receptor internalization by inhibiting p-arrestin 2 recruit to cell membrane.%目的 从前列腺素E2(PGE2)受体EP2和β-arrestin 2的表达分布变化特点,探讨PGE2诱导大鼠成纤维样滑膜细胞(FLS)异常增殖的分子机制以及芍药苷(Pae)的作用.方法 组织块培养法培养大鼠FLS,3H-TdR参入法检测FLS增殖情况,放免法测定细胞内环磷酸腺苷(cAMP)浓度,流式细胞术检测FLS胞膜EP2受体水平,Western blot法检测FLS EP2和β-arrestin 2总蛋白和胞膜蛋白的表达.结果 PGE2（125 μg·L-1）刺激24 h,诱导FLS的异常增殖,降低细胞内cAMP浓度和胞膜EP2受体水平,但上调胞膜β-arrestin 2表达和FLS中EP2、β-arrestin2的总表达,Pae可抑制FLS过度增殖,恢复cAMP水平和胞膜EP2表达,下调胞膜β-arrestin 2和总EP2、β-arrestin 2水平.结论 Pae可能通过抑制β-arrestin 2的表达和转膜,减少EP2受体内吞而升高cAMP,抑制FLS在PGE2作用下的异常增殖.
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