催乳素对葡萄球菌肠毒素A诱导的人外周血T细胞凋亡的影响

Effects of prolactin on human peripheral blood T cell apoptosis induced by staphylococcal enterotoxin A

目的探讨催乳素(PRL)在T细胞的活化诱导凋亡(activation induced cell death,AICD)中的作用。方法用葡萄球菌肠毒素(SEA)体外刺激人外周血T细胞作为T细胞AICD的模型,在第2次向模型中加入SEA诱导T细胞凋亡的同时,分别加入3种不同浓度的hPRL(20、300和1000 ng/ml)进行干预,同时设不含hPRL的对照组。0～24 h内,以MTT法检测T细胞的增殖情况。PI染色后用流式技术检测细胞凋亡情况,并通过琼脂糖凝胶电泳检测T细胞凋亡DNA。流式检测T细胞的Fas和FasL的表达水平变化。Western blot法检测T细胞内凋亡相关蛋白Bcl-2和Bax。结果在T细胞的AICD模型中高浓度PRL组(300、1000 ng/ml)其T细胞增殖得到显著维持(P<0.05),各PRL处理组T细胞凋亡率比对照组降低了32.9%～78.2%(P<0.05)。PRL组(300、1000 ng/ml)Bax/Bcl-2比值比对照组下降了44.4%～46.0%(P<0.05)。PRL可明显抑制细胞表面Fas和FasL的表达,其中各PRL处理组Fas的细胞阳性率比对照组下降了51.1%～75.0%(P<0.01),FasL的细胞阳性率比对照组下降了28.2%～39.1%(P<0.01)。结论在SEA诱导T细胞的AICD过程中,PRL可通过抑制Fas、FasL和Bax的表达,并提高Bcl-2的表达,来抑制T细胞凋亡,维持T细胞的增殖。

Objective To study the effects of prolactin（PRL） on T cell apoptosis in activation induced cell death （AICD）. Methods The model of T cell apoptosis was established from human peripheral blood mononuclear cells （PBMC） and induced by staphylococcal entemtoxin A （SEA）. Three different concentration PRL （20, 300, 1000 ng/ml） were applied to the AICD model when SEA were added again to induce the apoptosis ofT cells. Control group without PRL was set up at the same time. The proliferation of T cells was detected by MTr during 0-24 h. The apoptosis rate, the level of Fas and FasL of T cells was tested by flow cytometry （FCM） and DNA electrophoresis ladder . The content of Bax and Bcl - 2 of T cells was measured with Western blot . Results The proliferation of T cells was significantly maintained in 300 ng/ml and 1000 ng/ml PRL treated group （ P 〈 0.05）. Cell apoptosis rate of each PRL treated group decrease 32.9%-78.2% compared with control group （ P 〈 0.05）. Ratio of Bax/Bcl-2 in 300 ng/ml and 1000 ng/ml PRL treated group decreased 44.4%-46.0% compared with control group （ P 〈 0.05）. Expression of Fas and FasL was significantly suppressed by PRL. Positive cell rate of Fas and FasL of each PRL treated group decreased 51.1%-75.0% （ P 〈 0.01） and 28.2%-39.1% （ P 〈 0.01）, respectively. Conclusion In the process ofT cells AICD induced by SEA, PRL could inhibit the expression of Fas, FasL and Bax, and promote the expression of Bcl-2 to maintain the proliferation of T cells.