牛磺酸抗细胞因子诱导的原代培养胰岛细胞凋亡与抗凋亡蛋白A20的变化

Taurine protects cultured pancreatic islet cells against cytokine-induced apoptosis: implication of the anti-apoptotic protein A20

目的探讨白细胞介素-1β(IL-1β)、肿瘤坏死因子(TNF)和γ干扰素(IFNγ)引起的原代培养胰岛细胞凋亡与A20蛋白表达变化以及牛磺酸对其影响。方法用体外单层培养的方法,培养Wistar大鼠胰岛细胞,采用流式细胞仪、DNA电泳、放射免疫法及其RTPCR等分别观察I-L1β、TNF和IFN-γ对胰岛细胞凋亡细胞百分率、DNA片段、培养液中胰岛素分泌以及A20蛋白表达的影响,并进一步观察牛磺酸的作用。结果流式细胞仪分析显示IL1β、TNF和IFN-γ联合可诱导胰岛细胞凋亡率增加(从3.5%增加到30.2%),DNA明显片段化,同时胰岛素分泌明显降低(P<0.01),而A20蛋白无表达;牛磺酸能阻断上述细胞因子的作用(P<0.01)。结论牛磺酸能够改善细胞因子诱导的原代培养胰岛细胞凋亡,其机制可能与促进A20蛋白表达有关。

Objective To investigate the effects of taurine on the apoptosis of cultured pancreatic islet cells, the change of insulin secretion and A20 protein expression induced by the combination of IL-1β, TNF and IFN-γ. Methods After isolated, pancreatic islet cells from Wistar rat were incubated in monolayer in vitro and incubated with the combination of IL-1β, TNF and IFN-γ. Insulin secretion were detected, the protein expression of A20 was examined by RT-PCR, apoptosis was detected by flow cytometry and DNA electrophoresis, and the effects of taurine on the changes of them were further investigated. Results The combination of IL-β, TNF and IFN-γ induced a significant decrease of insulin content, flow cytometry analysis showed that apoptotic percentage of pancreatic islet cells remarkably increased （ from 3.5% to 30. 2% ） foUowing the addition of cytokines, agarose electrophoresis revealed special DNA ladder, the expression of A20 was not be found by means of RT-PCR. These effects were blocked by addition of taurine and A20 expression was up-regulated. Conclusion Taurine can attenuate the cytokine-induced apoptosis of cultured β cells, the mechanism of which may be by promoting the expression of A20.