y-氨基丁酸对炎性因子致胰岛细胞凋亡的保护作用

【目的】探讨1-氨基丁酸（gamma-aminobutyricacid，GABA）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】将胶原酶v：通过总胆管灌注到大鼠内，分离纯化大鼠胰岛细胞，并通过DTZ染色鉴定胰岛纯度。将新鲜分离的胰岛分为3组：正常对照组、通过白介素-1B（IL-1B）-y干扰素（IFN-7）建立胰岛细胞炎症模型（IL-1β＋IFN-1诱导组）、GABA干预组（GABA＋IL-1β＋IFN-1）。观察（IL-1β＋IFN-1）与GABA预孵育胰岛细胞的凋亡；二醋酸酯荧光素，碘化丙啶染色、流式细胞术及糖刺激实验检测胰岛细胞活性。凋亡率和功能，免疫荧光检测凋亡细胞Caspase-3蛋白表达。【结果】（IL-18＋IFN-7）组作用24h对胰岛细胞活性、凋亡率和糖刺激指数分别为20％、（32．7±5.3）％和（1．62±0．13），对照组3项指标分别为90％、（5．5±2．8）％和（2．37±0．11），两组比较差异显著（P〈0．01）；（GABA＋IL-1β＋IFN-y）组3项指标分别为70％、（18．0±6．3）％和（1．97±0．12），与（IL-1β＋IFN-1）组比较，均有明显差异（P〈0．01）。（IL-1β＋IFN-1）组胰岛的Caspase-3蛋白表达明显增加，而（GABA＋IL-1β＋IFN-1）组胰岛的Caspase-3蛋白表达明显受到抑制。【结论】联合IL-1β及IFN-y明显诱导胰岛细胞凋亡，GABA显著抑制IL-1β及IFN-1诱导的胰岛细胞凋亡，其机制可能与降低Caspase-3蛋白的表达有关。

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

[ Objective ] To investigate the protective effect of GABA on islet cell apoptosis induced by proinflammatory cytokines and its mechanism. [ Methods ] 250 to 300 g rats were in situ perfused with collagenase V in common bile duct after anesthesia. Islet cells of rats were purified by Histopaque 1 077 density gradient centrifugation, and the purity of isletcells was detected by DTZ. Purified islet cells were randomly divided into 3 groups, normal control group （ control group）, interleukin-1 13 （ IL-1 13 ） and interferon- Y （IFN- Y） （IL-1 13 ＋ IFN-Y, group）, and GABA, IL-1 13, and IFN-Y （GABA ＋IL-1 13 ＋IFN-Y group）, respectively. The survival rate, apoptosis rate, cytoactive and caspase-3 specific activity of Islet cells were determined by FDA/PI, flow cytometry, glucose stimulation and immunofluorescence, respectively. [ Results ]The survival rate, apoptosis rate and stimulation index of glucose were 90%, （5.5 ± 2.8）% and （2.37 ± 0.11） in control group, 20%, （32.7 ± 5.3）% and （1.62 ± 0.13） in IL-1 13 ＋IFN- Ygroup, and 70%, （18.0 ± 6.3）% and （1.97± 0.12） in GABA ＋IL-1 13 ＋IFN- Y group. There were significant differences in the survival rate, apoptosis rate, and stimulation index of glucose between IL-1 13 ＋IFN- Y group and GABA ＋IL-1 13 ＋IFN- Y group （all P 〈 0.01）. Moreover, the caspase-3 protein expression in IL-1 13 ＋ IFN- group was significantly increased as compared with the control group. But the caspase-3 protein expression was significantly inhibited in GABA ＋ IL-1 13 ＋ IFN-Y group. [Conclusions] Combined application of IL-1 13 and IFN-Y could induce islet cell apoptosis. The pretreatment with GABA could protect islet cells from apoptosis, and the protective effect of GABA is correlated with down-regulation of caspase-3 activity.