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目的:探讨银杏酮酯(GBE50)抗自然衰老大鼠前额叶皮层(prefrontal cortex,PFC)氧化DNA损伤和延缓端粒长度的作用及SIRT1在其中的作用机制。方法:建立自然衰老大鼠模型,用GBE50(100mg/kg)每日灌胃,连续60天。免疫荧光双标观察PFC中8-OHDG的亚细胞定位及表达强度;荧光定量PCR(Real time-PCR)检测PFC全基因组DNA相对端粒长度;Western-blot检测SIRTl、p53和p21的蛋白水平。结果:免疫荧光双标结果显示8-OHDG主要位于PFC神经元胞体中。与青年对照组相比,自然衰老大鼠PFC神经元8-OHDG表达增加,GBE50(100mg/kg)处理后减少。RT-PCR结果显示:与青年对照组相比,自然衰老大鼠PFC相对端粒长度缩短,GBE50(100mg/kg)处理后相对端粒长度缩短延缓。Western blot结果显示:与青年对照组相比,自然衰老大鼠PFC的SIRTl蛋白表达下降,p21蛋白表达增加;GBE50(100mg/kg)处理后自然衰老大鼠PFC的SIRTl蛋白表达增加,p21蛋白表达有下降趋势;而p53蛋白变化不明显。结论:GBE50(100mg/kg)可降低自然衰老大鼠PFC内8-OHDG表达,延缓相对端粒长度缩短,其过程可能与SIRT1、p21蛋白表达有关。
Objective: To investigate the effect of GBE50 on the oxidative DNA damage and telomere length reduction of prefrontal cortex (PFC) in rats and the mechanism of SIRT1 in it. Methods: A natural aging rat model was established. The rats were gavaged with GBE50 (100mg / kg) daily for 60 consecutive days. The subcellular localization and expression intensity of 8-OHDG in PFC were observed by immunofluorescence double staining. The relative telomere length of whole genome DNA of PFC was detected by Real-time PCR. The protein levels of SIRT1, p53 and p21 were detected by Western-blot. Results: Immunofluorescence double-labeled results showed that 8-OHDG mainly located in the PFC neuronal cell body. Compared with the young control group, the expression of 8-OHDG in PFC neurons in naturally aged rats increased, and decreased after treatment with GBE50 (100mg / kg). RT-PCR results showed that compared with the young control group, the relative telomere length of PFC in spontaneous aging rats was shortened, and the relative telomere length shortening was delayed after treatment with GBE50 (100 mg / kg). The result of Western blot showed that SIRT1 protein expression and p21 protein expression of PFC in naturally aged rats were decreased compared with those in young control rats. The SIRT1 protein expression and P21 protein expression of PFC in naturally aged rats were increased after treatment with GBE50 (100mg / kg) There is a downward trend; while the p53 protein change is not obvious. CONCLUSION: GBE50 (100 mg / kg) can reduce the expression of 8-OHDG in PFCs and delay the relative telomere shortening in spontaneous aging rats, which may be related to the expression of SIRT1 and p21 protein.