【作者】 李美端；

【导师】 廖惠珍；

【作者基本信息】 福建医科大学 ， 卫生毒理学， 2007， 硕士

【摘要】 目的研究摄入不同剂量α-硫辛酸对D-半乳糖过氧化损伤小鼠的影响效应,侧重其对小鼠海马功能的作用并初探其机制,为其在慢性疾病和其它医学领域的推广应用提供科学参考。方法清洁级雌性昆明种小鼠按体重随机分为五组:空白对照组(? )、模型组(П)、α-硫辛酸干预组(Ш、?V、V),除空白对照组外,其余四组均用D-半乳糖(100mg/kgBW)(1ml/100gBW)颈背部皮下注射,空白对照组给予同体积的生理盐水注射(1ml/100gBW),每日一次,连续6周,第7周开始,三个α-硫辛酸干预组小鼠经口给予不同浓度α-硫辛酸(50mg/kgBW、100mg/kgBW、200mg/kgBW)(0.5ml/100gBW),对照组、模型组给予同体积溶剂(0.5ml/100gBW)灌胃,同时,模型组和α-硫辛酸干预组继续给予D-半乳糖颈背部皮下注射,连续8周。干预结束后收集相关标本进行抗氧化相关指标、海马神经细胞DNA损伤、海马CA1区神经型一氧化氮合酶表达的测定。结果1、α-硫辛酸对小鼠抗氧化能力的影响1.1提高红细胞SOD活力:D-半乳糖可使小鼠红细胞SOD活力下降,模型组和对照组比较有统计学意义(P<0.05),不同剂量的α-硫辛酸均可提高SOD活性,并呈剂量-反应关系(P<0.05),和模型组比较有统计学意义(P<0.05)。1.2降低血清LPO含量:D-半乳糖可使小鼠血清LPO水平升高,模型组和对照组比较有统计学意义(P<0.05),不同剂量的α-硫辛酸均可降低小鼠血清LPO含量,和模型组比较有统计学意义(P<0.05),低剂量组和对照组比较有统计学意义(P<0.05)。1.3降低肝组织LPO含量:D-半乳糖可使小鼠肝组织LPO水平升高,模型组和对照组比较有统计学意义(P<0.05),不同剂量的α-硫辛酸均可降低小鼠肝组织LPO含量,仅高剂量组和模型组比较有统计学意义(P<0.05),干预组和对照组比较有统计学意义(P<0.05)。1.4降低脾脏LPO含量:D-半乳糖可使小鼠脾组织LPO水平升高,模型组和对照组比较有统计学意义(P<0.05),不同剂量的α-硫辛酸均可降低小鼠脾脏LPO含量,但和模型组比较,仅高剂量组有统计学意义(P<0.05),干预组和对照组比较有统计学意义(P<0.05)。1.5降低脑组织脂褐质水平:D-半乳糖可使小鼠脑组织脂褐质水平升高,模型组和对照组比较有统计学意义(P<0.05),不同剂量的α-硫辛酸均可降低小鼠脑组织脂褐质水平,和模型组比较有统计学意义(P<0.05),高剂量组和低剂量组有显著性差别(P<0.05)。2、α-硫辛酸对海马神经细胞DNA损伤的修复效应:模型组小鼠海马彗星细胞尾长、尾矩、Olive尾矩值均最大,对照组的均最小,对照组和模型组比较有统计学意义(P<0.05),三个α-硫辛酸干预组的各指标均小于模型组,有统计学意义(P<0.05)。3、海马CA1区神经型一氧化氮合酶表达的影响:模型组小鼠海马CA1区神经型一氧化氮合酶水平最低,空白对照组最高,和模型组比较,不同剂量α-硫辛酸干预组小鼠海马CA1区神经型一氧化氮合酶表达显著增高(P<0.05),对照组高于各干预组,差别无统计学意义。结论:1、α-硫辛酸具有清除自由基,增强体内抗氧化系统功能的作用,且存在剂量-反应关系。2、α-硫辛酸可以有效地减少D-半乳糖引起的海马神经细胞DNA的断裂损伤。3、α-硫辛酸能够逆转D-半乳糖所致的海马CA1区神经型一氧化氮合酶表达下调。更多还原

【Abstract】 Objectiveα-lipoic acid has been a focus of medical research for years,especially its potent antioxidative power. In this months-long study, we observed its restoration of the endogenous antioxidative system, effects on DNA oxidative damage of hippocampus neurons and upgradation of nNOS expression of mice hippocampus CAI subregion, supplying scientific evidence for its application on medicine.Method50 pure Kuming female mice were weighed and assigned randomly into blank control group (?), model group (П) and threeα-lipoic acid groups (Ш,IV, V).Model group and threeα-lipoic acid groups took D-galactose by subcutaneous injection once per day for 14 weeks (100mg/kgBW) (0.1ml/10gBW),meanwhile mice of blank control group were given isotonic Na chloride(0.1ml/10gBW) .In the last 6 weeks, while the subcutaneous injection was undergoing as previous, threeα-lipoic acid groups were given different doses ofα-lipoic acid mixed in colleseed oil (pretreated by alcohol and high temperature) (0.05ml/10gBW) via intragastric administration (Ш,IV, V)( 50mg/kgBW、100mg/kgBW、200mg/kgBW),meanwhile blank control group and model group were given colleseed oil(0.05ml/10gBW)too.Results:1、Effects on the endogenous antioxidative ability1.1 Reversed D-galactose-caused decline of erythrocyte superoxide dismutase (SOD) activity: Model group was satistically significantly lower than other groups (P<0.05). Compared to model group, SOD activity of the three groups of mice administered withα-lipoic acid was higher (P<0.05).The higher the dose ofα-lipoic acid, the higher SOD activity (P<0.05). 1.2 Reduced blood serum LPO levels: LPO levels of model group were statistically significantly higher than those of blank control group (P<0.05), Feeding rats theα-lipoic acid diet reduced LPO levels markedly (P<0.05). The higher the dose ofα-lipoic acid, the lower LPO levels (P>0.05).1.3 Reduced LPO levels in livers: LPO levels of liver in model group were higher than those in blank control group (P<0.05). Between the threeα-lipoic acid group, the higher the dose ofα-lipoic acid, the lower LPO levels (P>0.05), Only high dose ofα-lipoic acid could completely reversed increase of LPO levels in liver caused by D-galactose (P<0.05).1.4 Reduced LPO levels in spleen: LPO levels of spleen in model group were markedly higher than those in blank control group (P<0.05), Only high dose ofα-lipoic c acid could completely reversed increase of LPO levels in spleen caused by D-galactose (P<0.05).1.5 Reduced brain lipofuscin levels: The LF in brain of model group was markedly higher than that of blank control group (P<0.05), which could be reversed by different doses ofα-lipoic acid (P<0.05).2、Protective effects on DNA oxidative damage of miec hippocampus. TailLength,TailMoment and OliveTailMoment of comet-like cells in hippocampus of model group were satistically significantly different from other groups( P<0.05).The D-galactose induced DNA oxidative damage was nearly restored to norm byα-lipoic acid (P<0.05).3、Improvement of nNOS expression in hippocampus CA1 subregion. Compared to model group mice, nNOS expression levels in hippocampus CA1 subregion ofα-lipoic acid groups were upgraded highly (P<0.05), Among the five groups, the contents of nNOS in model group were lowest (P<0.05).Conclusion1、α-lipoic acid could eliminate free radicals and strengthen the endogenous antioxidative system, thus relieved oxidative stress.Dose-effect association existed.2、α-lipoic acid was capable of repairing DNA oxidative damage which was induced by D-galactose. 3、D-galactose lowered expression of nNOS in mice hippocampus CA1 subregion, which was reversed byα-lipoic acid.更多还原