中文摘要：

目的观察热休克转录因子1（HSF1）与热休克蛋白70（HSP70）对紫外线A（UVA）诱导HaCaT细胞凋亡的保护作用及其机制。方法建立8mJ/cm2UVA辐射损伤HaCaT细胞的病理模型。将细胞随机分为对照组、8mJ/cm2UVA照射组、HSP70转录抑制剂组（50μmol/L槲皮素）。Honechst 33258荧光染色观察细胞凋亡;蛋白质印迹法检测UVA辐射HaCaT细胞后p-HSF1和HSP70蛋白的经时变化及UVA辐射后孵育6h JNK（c-Jun氨基末端激酶）、p-JNK的蛋白表达;Real-Time PCR检测HSP70 mRNA的表达。结果 UVA辐射后HaCaT细胞内p-HSF1、HSP70蛋白表达量均出现先增加后减少的时间依赖性趋势,其中p-HSF1于1h开始增加,3h达高峰,HSP70于6h达高峰,24h基本恢复原始水平;UVA辐射前预先加入HSP70转录抑制剂槲皮素能显著抑制HSP70 mRNA的表达,增加p-JNK的表达量,同时Honechst 33258荧光染色观察其与UVA辐射组比较凋亡率明显升高。结论 8mJ/cm2UVA辐射HaCaT细胞在一定时间内可使HSF1活化致HSP70表达增加。HSF1/HSP70通路对UVA诱导的HaCaT细胞凋亡具有保护作用,其机制与HSP70大量表达后抑制JNK的活化有关。

英文摘要：

Objective To investigate the protective effect of heat shock factor1（HSF1） and heat shock protein70（HSP70） on ultraviolet A（UVA）-induced HaCaT cells apoptosis and its mechanism.Methods The apoptotic HaCaT cell model was induced by UVA irradiation（8mJ/cm2）.The cells were randomly divided into three groups,including a control group,a model group（8mJ/cm2 UVA） and a HSP70 transcription inhibitor group（50 μmol/L quercetin）.The morphologic alteration of apoptotic cells was investigated by using Hoechst 33258 fluorescent staining.Western blotting was used to investigate protein expression levels of phosphorylated HSF1 and HSP70 at different time points,as well as c-Jun N-terminal kinase（JNK） and phosphorylated JNK were investigated after incubating for 6 hours following UVA irradiation.HSP70 mRNA was detected by Real-Time PCR.Results Protein expression levels of both phosphorylated HSF1 and HSP70 were time-dependent,appearing an increase at first and then decreased.The increase of p-HSF1 begining at 1h,up to the peak at 3h;and the increase of HSP70 to the peak at 6h and then recovered to the original level at 24h.The pretreatment of HSP70 transcription inhibitor quercetin could significantly inhibit the expression of HSP70 mRNA,and increase the expression of phosphorylated JNK,while increase the apoptosis rate in comparison with UVA model group observed by using Hoechst 33258 fluorescent staining.Conclusion 8mJ/cm2 UVA irradiation could stimulate the activation of HSF1 and increase HSP70 protein expression.HSF1/HSP70 pathway has a protective effect on UVA-induced HaCaT cells apoptosis and its mechanism is that a large number of HSP70 expression inhibited the activation of JNK.