内吗啡肽对过氧化氢诱导的大鼠胰岛损伤的保护作用

目的 研究过氧化氢(H2O2)对胰岛的损伤及内吗啡肽(EMs)对这种损伤的保护作用.方法 成年雄性Wistar大鼠18只,体质量200～300 g,体外分离、纯化和培养Wistar大鼠胰岛,双硫腙(DyTZ)染色鉴定,锥虫蓝染色检测细胞活力,葡萄糖刺激实验检测胰岛生物活性.四唑蓝(MTT)分析不同浓度的H2O2对胰岛的...

Effect of endomorphins on H2O2 -induced islet injury in rats

Objective To evaluate the effects of endomorphin (EMs) on pancreatic islet injuries induced by H2O2. Methods Eighteen wistar rats' islets were isolated and purified,then identified by dithizone staining. The viability was determined by the Trypanblue exclusion assay. The function of the islets was examined by the insulin releasion response to glucose stimulation. MTT assay was used to analysis the effects of EMs on pancreatic islet injuries induced by H2O2. The medium insulin accumulation was measured by radioimmunoassay. The cell cycle distribution was analyzed by PI staining flow cytometric analysis. The protein level of p21 was detected by western blot. Results In the cultured cells in vitro,the ratio of islet cells was 95% ±2% and the cell viability was 96% ± 3%. Glucose stimulation experiments identified the islet cells could execute normal biology function. Compared with control group ( ( 153 ± 11 ) mU/L),insulin accumulation of cells supernatant in H2O2 groups ( ( 67 ± 9 ) mU/L) was significantly decreased ( P ＜ 0. 01 ),while EMs enhanced the insulin accumulation of cells supernatant under H2O2 ( P ＜0. 05 ). The cell number of cell cycle G0/G1 phase in H2O2 treatment group (63.9% ±3. 1% ) was significantly higher than that in control group(41.3% ± 1.9% ),and S phase cell number in H2O2 treatment group (27.2% ± 1.1% ) was significantly lower than control ( 35. 3% ± 2.6% ). The cell number of cell cycle G0/G1 phase in H2O2 treatment group induced by EM1 (44.4% ± 2. 1% ) was significantly lower than that in H2O2 treatment group (66.9% ±3. 1% ,P ＜0.05),and S phase cell number in H2O2 treatment group induced by EM1 ( 32. 1% ± 1.2% ) was significantly higher than H2O2 group (24. 2% ± 1. 1%,P ＜ 0. 05 ). The results also showed the cell number of cell cycle Go/G1 phase in H2O2 treatment group induced by EM2 (47.6% ±2. 8% ) was significantly lower than that in H2O2 group(66. 9% ± 3. 1%,P ＜0. 05),and S phase cell number in H2O2 treatment group induced by EM2 ( 31.2% ± 1.8% ) was significantly higher than H2O2group(24. 2% ± 1.1% ,P ＜ 0. 05 ). Conclusions Taken together,the present study demonstrated that endomorphins could protect islets from H2O2-induced injuries,and these protection roles might due to the down-regulation of p21 protein and the antioxidant damage.