杜仲叶提取物对乙醇导致的小鼠小脑和大脑皮层DNA损伤的保护作用

Protective Effect of Eucommia folium Extract against DNA Damage in Cerebellum and Cerebral Cortex of Mice Induced by Ethanol

选取176只雄性昆明种小鼠,随机分为空白组、模型组、阳性组、杜仲叶不同提取物的高(400 mg/kg)、低(100 mg/kg)剂量组,彗星实验每组4只,生化指标测试实验每组28只.采用彗星实验筛选杜仲叶(Eucommia folium)95%醇提物、50%醇提物和水提物对乙醇所致小鼠小脑和大脑皮层DNA损伤的保护作用,确定最佳提取物;通过酶联免疫方法和比色法检测杜仲叶最佳提取物对乙醇引起小鼠小脑、大脑皮层组织氧化损伤相关生理指标的影响,如一氧化氮(NO)、丙二醛(MDA)、8-羟基脱氧鸟苷(8-OHdG)和醌氧化还原酶1(NQO1)的含量,以及总超氧化歧化酶(T-SOD)、谷胱甘肽过氧化物酶(GSH-P_X)和胆碱乙酰转移酶(ChAT)的活力.采用改良福林酚(FC)比色法,测定杜仲叶最佳提取物中总多酚的含量.结果显示,杜仲叶50%醇提物可显著改善乙醇引起的急性脑神经DNA损伤,保护作用强于杜仲叶95%醇提物和水提物.50%醇提物显著降低小鼠小脑和大脑皮层组织中MDA、NO、8-OHdG和NQO1的水平,提高GSH-P_X、T-SOD和ChAT的活性.采用FC比色法测定杜仲叶50%醇提物中总多酚的含量为62.7%.以上结果表明:杜仲叶50%醇提物可能通过提高脑组织抗氧化的能力,达到保护脑神经DNA的作用;在保护脑神经DNA和抗氧化作用中,总多酚类成分发挥了极其重要的作用.

176 male Kunming mice were randomly divided into blank group, model group, positive group, and the high(400 mg/kg), low-dose groups(100 mg/kg) with 4 mice in each group for comet assay and 28 mice in each group for biochemical index test. The comet assay was used to evaluate 95% alcohol extract of Eucommia folium, 50% alcohol extract and water extract on the protective effect of Eucommia folium against DNA damage caused by ethanol in the cerebellum and cerebral cortex of mice. The best extraction method was confirmed. The biochemical indexes related to oxidative damage were detected in cerebellum and cerebral cortex of mice by enzyme-linked immune method and colorimetric method, such as nitric oxide(NO), malondialdehyde(MDA), 8-hydroxydeoxy guanosine(8-OHdG), quinone oxidoreductase 1(NQO1), total super oxide dismutase(T-SOD), glutathione peroxidase(GSH-P_X) and choline acetyltransferase(ChAT). The content of total polyphenols in the extract of Eucommia folium was determined by using modified FC colorimetry. The results showed that 50% ethanol extract of Eucommia folium could significantly improve DNA damage in mouse brain caused by ethanol, and the protective effect was stronger than 95% alcohol extract and water extract of Eucommia folium.The 50% ethanol extract extremely reduced the levels of MDA, NO, 8-OHdG and NQO1 in the cerebellum and cerebral cortex of mice, and increased the activities of GSH-P_X, T-SOD and ChAT. The concentration of total polyphenols in 50% alcohol extract of Eucommia folium was 62.7% by using modified FC colorimetry. The above results indicated that 50% alcohol extract of Eucommia folium may protect brain nerve DNA by improving the antioxidant capacity of brain tissue. Total polyphenols play an extremely important role in protecting brain nerve DNA and anti-oxidative effect.