格列酮类药物通过PPARγ依赖性机制保护胰岛β细胞免受致病性炎症因子的破坏

Glitazones protects beta cell function from cytotoxic cytokines through PPAR gammadependent mechanisms

目的探讨罗格列酮和吡格列酮对致病性炎症因子破坏胰岛β细胞的保护作用,并研究其保护作用是否呈PPARγ依赖性。方法用致病性炎症因子IL-1β和IFN-γ处理NIT-1胰岛β细胞株,建立β细胞的炎症损伤模型,观察不同浓度的罗格列酮或吡格列酮对炎症所致β细胞损伤的作用。使用流式细胞仪用AnnexinV-FITC/PI检测各组细胞的凋亡率,用ELISA方法检测各组细胞的胰岛素分泌能力。同时用PPARγ的特异性抑制剂GW9662和PPARγ-SiRNA阻断PPARγ,观察对各组细胞的影响。结果 1)10μmol/L的罗格列酮和吡格列酮可显著性减少致病性炎症因子引起的β细胞凋亡(凋亡率分别为13.99%和16.67%vs51.33%,P<0.01);1μmol/L和20μmol/L的罗格列酮和吡格列酮亦可减少β细胞凋亡,其中以10uM干预浓度保护作用最明显;2)IL-1β/IFN-γ组细胞的胰岛素浓度由正常对照组的8.5±0.6ng/ml下降至3.6±0.5ng/ml;而10μmol/L的罗格列酮和吡格列酮处理组细胞的胰岛素分泌能力有所恢复,可达6.8±0.7ng/ml、5.9±0.9ng/ml(与炎症因子组相比,P<0.01)。3)使用GW9662和PPARγ-SiRNA特异性阻断PPARγ后,罗格列酮和吡格列酮的保护作用几乎100%消失,与IL-1β/IFN-γ组的β细胞凋亡和胰岛素分泌水平相似。结论格列酮类药物可以通过PPARγ依赖性机制保护致病性炎症因子对β细胞的损伤,减少β细胞凋亡,恢复胰岛素分泌能力。

Objective To investigate the protective effects of glitazones on islet beta cells and PPAR gamma dependence of such effects. Methods IL-1β and IFN-γ were used to treat NIT-1 cells, a beta cell line, to induce beta cell damage. The cells were pretreated with posiglitazone and pioglitazone at different concentrations to study the protective effects of these drugs. The cell apoptosis rate was determined with Annexin V-FITC by flow cytometry, and the insulin secretion capacity of the cells was assessed with ELISA. GW9662 and PPARγ-SiRNA were used to specifically inhibit PPAR to investigate the PPAR gamma-dependent mechanisms. Results Rosilglitazone and pioglitazone at 10 μmol/L could significantly decrease the apoptosis of beta cells induced by the cytokines （apoptotic rates of 13.99% and 16.67% vs 51.33%, P0.01）. Rosilglitazone at 10 μmol/L and pioglitazone at 20 μmol/L were less effective than 10 μmol/L rosiglitazone and pioglitazone. The insulin secretion of the cytokine-treated cells decreased from 8.5±0.6 ng/ml of the control group to 3.6±0.5 ng/ml, while rosiglitazone and pioglitazone could increase the insulin secretion to 6.8±0.7 ng/ml and 5.9±0.9 ng/ml, respectively. When PPAR gamma was specifically inhibited by GW9662 and PPARγ-SiRNA, the protective effects of rosiglitazone and pioglitazone were almost undetectable, and the apoptotic rate increased and insulin secretion decreased to the level of the cytokine-treated cells. Conclusion Glitazones can protect beta cells from apoptosis and impairment of insulin secretion function resulting from the cytotoxic cytokines via a PPAR gamma-dependent mechanism.