吡格列酮对炎性因子所致胰岛细胞凋亡的保护作用

Protective effect of pioglitazone on islet cell apoptosis induced by proinflammatory cytokines

目的:探讨Ppar-γ激动剂吡格列酮(PGZ)对炎性因子所诱导的胰岛细胞凋亡的保护作用,初步研究其作用机制。方法:Western-blotting检测NIT-1细胞的Ppar-γ受体蛋白表达;联合IL-1β及IFN-γ作用于体外培养的胰岛细胞株NIT-1,建立胰岛细胞炎症模型,观察(IL-1β+IFN-)γ与PGZ预孵育NIT-1细胞的凋亡;MTT法、流式细胞术检测细胞生长抑制率及凋亡率,比色法检测凋亡细胞caspase-3比活性。结果:NIT-1细胞表达Ppar-γ蛋白;(IL-1β+IFN-)γ组作用24 h对NIT-1细胞生长抑制率、凋亡率c、aspase-3比活性分别为49.8%、28.0%、3.5,对照组3项指标分别为0%、4.3%、1,两组比较均有十分显著差异(P<0.01);PGZ组3项指标分别为2.7%、7.1%、1.3,与对照组比较,均无明显差异(P>0.05);(PGZ+IL-1β+IFN-)γ组的3项指标分别为18.6%、14.8%、1.5,与(IL-1β+IFN-)γ组比较均有差异(P<0.05),与对照组比较分别为P>0.05,P<0.05,P<0.05。结论:NIT-1细胞表达Ppar-γ受体蛋白;联合IL-1β及IFN-γ明显诱导NIT-1细胞凋亡,PGZ显著抑制IL-1β及IFN-γ诱导的NIT-1细胞凋亡,其机制与降低caspase-3活性有关。

Objective： To investigate the protective effect of pioglitazone （PGZ）, a PPAR-γ agonist, on islet cell apoptosis induced by pminflammatory cytokines and its mechanism. Methods： The expression of PPAR-γ protein in NIT-1 cells was identified by Western blotting assay. The NIT-1 cells were treated with PGZ （PGZ group）, interleukin-l[3 （1L-113）and interfemn-γ （IFN-γ）（1L-1β＋IFN-γ group）, and PGZ, IL-1β, and IFN-γ （PGZ＋IL-1β＋IFN-γ group）, respectively. The growth inhibition rate, apoptosis rate, and caspase-3 specific activity of NIT-1 cells were determined by MTT, flow cytometry, and colorimetric assay, respectively. Results： NIT-1 cells expressed PPAR-γ protein. The growth inhibition rate, apoptosis rate, and caspase-3 specific activity were 49.8%, 28.0%, and 3.5 in IL-1β＋IFN-γ group and 0%, 4.3%, and 1 in control group. There were significant differences in the growth inhibition rate, apoptosis rate, and caspase-3 specific activity between these 2 groups （all P 〈 0.01 ）. There was no significant difference in the growth inhibition rate, apoptosis rate, and caspase-3 specific activity between PGZ group and control group （2.7% vs. 0%, 7.1% vs. 4.3%, and 1.3 vs. 1, repecitvley, all P 〉 0.05）. The growth inhibition rate, apoptosis rate, and caspase-3 specific activity were 18.6%, 14.8%, and 1.5 in PGZ＋IL-1β＋IFN-γ, group. There were significant differences in the growth inhibition rate, apoptosis rate, and caspase-3 specific activity between PGZ＋IL-1β＋ IFN-γ, group and 1L-1β＋IFN-γ, group （all P 〈 0.05）, but only significant differences in the apoptosis rate and caspase-3 specific activity were found between PGZ＋I1β＋IFN-γ, group and control group（both P 〈 0.05 ）. Conclusion： PPAR-γ, protein is expressed in NIT-1 cells. Combined apphcafion of IL-1β and IFN-γ, could induce NIT-1 cell apoptosis. The pretreatment with PGZ could protect NIT-1 cells from apoptosis, and the pm/ective effect of PGZ is correlated with down-regulation of caspase-3 activity.