噻唑烷二酮类药物抑制白介素1β和干扰素γ诱导的胰岛β细胞凋亡

Inhibitory effects of thiazolidinedione upon cytokine-induced apoptosis in pancreatic β-cell line

目的观察噻唑烷二酮类药物（TZD）抑制白介素1β（IL-1β）和干扰素γ（IFN-γ）诱导胰岛β细胞凋亡的作用及对胰岛素分泌功能的影响，探讨其可能的作用机制。方法体外培养小鼠胰岛素瘤细胞（NIT-1）至指数增长期，根据干预方案进行分组：正常细胞组、IL-1β／IFN-γ组、罗格列酮（RSG）或吡格列酮（PIG）＋IL-1β/IFN-γ组、RSG或PIG＋IL-1β／IFN-γ＋GW9662组。采用Hoechst33342染色观察细胞凋亡形态变化、膜联蛋白V-FITC／PI检测凋亡率、ELISA检测胰岛素分泌，观察RSG和PIG对IL-1β和IFN-γ损伤B细胞的保护作用。结果RSG或PIG＋IL-1β／IFN-γ组凋亡率明显降低（14．0％、16．7％），与IL-1β／IFN-γ组比较差异有统计学意义（51．3％，P〈0．01）；RSG或PIG＋IL-1β和IFN-γ＋GW9662组凋亡率明显升高（41．4％、44．7％），与RSG或PIG＋IL-1β／IFN-γ组比较差异有统计学意义（P〈0．01）；同样，RSG或PIG＋IL-1β／IFN-γ组葡萄糖刺激胰岛素分泌能力（GSIS）明显恢复[（6．8±0．7）ng／ml、（5．9±0．9）ng／ml]，与IL-1β／IFN-γ组（3．6±0．5ng／ml）比较差异有统计学意义（P〈0．01）；RSG或PIG＋IL-1B和IFN-γ＋GW9662组GSIS明显降低[（3．9±0．4）ng/ml、（3．6±0．3）ng／ml]，与RSG或PIG＋IL-1β／IFN-γ组比较差异有统计学意义（P〈0．01）。结论TZD可以抑制细胞因子诱导的胰岛β细胞凋亡和恢复β细胞的胰岛素分泌功能，其机制可能与抑制半胱氨酸水解酶-3的活性有关。

Objective To investigate the protective effects and potential mechanisms of TZD upon pancreatic β-cells. Methods Apoptosis was induced in vitro by interleukin-1β （IL-1β） and interferon-γ （IFN-γ）. After treatment with rosiglitazone （RSG）/ pioglitazone （PIG） at the final concentrations of 1 μmol/L, 10 μmol/L, 20 μmol/L respectively, the apoptotic rate of NIT-γ cells was determined by Hoechest33342 staining and Annexin V-FITC/PI flow cytometry respectively. Caspase-3 specific activity of NIT-1 cells was determined by Caspase-3 assay and insulin secretion measured by ELISA. Results After treatment of different concentrations of RSG/PIG, the apoptotic rate of NIT-1 cells decreased to 29. 3%, 14. 0%, 28.1% and 27.4%, 16. 7%, 23.5% respectively. There were significant differences in apoptotic rate between the RSG/PIG treatment group and IL-1 β/IFN-γ group （P 〈0. 01 ）. After treatment with RSG/ PIG, glucose-stimulated insulin secretion （GSIS） of NIT-1 cells recovered in different degrees [ （6.8 ± 0. 7）ng/ml, （5.9±0. 9）ng/ml,P 〈0.01 ]. There were significant differences in GSIS between the RSG/ PIG treatment group and IL-1β/IFN-γ group （P 〈 0. 01 ）. Moreover, most of the protective effects of TZD upon pancreatic β-cells could be blocked by a PPAR-γ inhibitor, GW9662. Conclusion TZD might protect pancreatic β-cells directly via inhibiting cytokine-induced apoptosis and recovering insulin secretion. And the mechanism may be correlated with the down-regulation of caspase-3 activity.