槲皮素对热应激后神经胶质瘤细胞凋亡及热激蛋白表达的影响

目的探讨槲皮素对神经胶质瘤细胞(C6细胞)凋亡的影响及作用机制。方法 C6细胞加入槲皮素0~200μmol·L-1培养1 h后,于42℃水浴加热1 h,再正常培养12 h。MTT法检测C6细胞存活率,Hoechst/PI双染法,annexinⅤ-FITC/PI双染检测细胞凋亡率,Western印迹法检测热激蛋白70(HSP70)表达。结果与正常对照组相比,加热组细胞存活率和细胞凋亡率均无明显改变,但加热组HSP70表达水平从正常对照组的0.22±0.01升高到0.36±0.02(P<0.01)。槲皮素能明显抑制C6细胞增殖,槲皮素50,100,150和200μmol·L-1细胞存活率分别为103%,86%,77%和75%,呈浓度依赖性(r=0.94,P<0.05)。槲皮素50,100和200μmol·L-1显著诱导C6细胞凋亡(P<0.05)。与加热组相比,随着槲皮素浓度的增加,C6细胞早期和晚期凋亡率均明显增加,最高细胞凋亡率为59%,槲皮素200μmol·L-1处理后明显降低了加热导致的HSP70表达增加,降低了53%(P<0.01)。结论槲皮素可以抑制HSP70表达并诱导神经胶质瘤细胞凋亡。

Effect of quercetin on heat-induced glioma cell apoptosis and expression of heat shock protein

OBJECTIVE To investigate the effect of quercetin on glioma cell apoptosis and the mechanisms thereof. METHODS The glioma C6 cells were treated with quercetin 0-200 μmol·L^-1 for 1 h before they were heated in a 42℃ water bath for 1 h, followed by culturing at 37℃ in a humidified atmosphere of 5% CO₂ for 12 h. The cell viability was assessed by MTT assay. Apoptosis was assessed by annexinⅤ-FITC and PI staining followed by analysis with flow cytometry. Expression of heat shock protein 70 (HSP70) was assessed by Western blot analysis. RESULTS There was no difference in cell viability and cell apoptosis between control group and heat-shock group. But the HSP70 expression increased from 0.22±0.01 in normal control group to 0.36±0.02 in heat-shock group（P<0.01）. The viability of cells was significantly decreased by quercetin 50，100，150 and 200 μmol·L^-1, and respectively was 103%, 86%, 77% and 75%, showing a concentration- dependent manner (r=0.94, P<0.05). Quercetin 50, 100 and 200 μmol·L^-1 significantly induced C6 cells apoptosis (P<0.05). Compared with heat-shock group, the rate of apoptosis, early or late was significantly enhanced with the increase in the concentrations of quercetin, while the highest apoptosis rate in C6 cells was 59%. HSP70 expression was decreased by 53% with quercetin 200 μmol·L^-1 treatment in comparison with heat-treat group (P<0.01).CONCLUSION Quercetin shows the ability to suppress the expression of HSP70 impelled brain glioma cell apoptosis.