丹参多酚酸盐B对糖尿病大鼠认知功能及突触可塑性的影响

Effects of salvianoic acid B on cognitive function and synaptic plasticity in diabetic rats

目的 探讨丹参多酚酸盐B(Sal B)是否通过调节突触可塑性蛋白的表达水平改善糖尿病(DM)大鼠学习和记忆障碍.方法 30只雄性SD大鼠按随机数字表法分为正常对照组(CON组,n=10),DM模型组(DM组,n=10),Sal B组(n=10).腹腔注射链脲佐菌素(STZ)55 mg/kg建立DM大鼠模型,当大鼠血糖≥16.7 mmol/L为制模成功.成模后,Sal B组大鼠腹腔注射Sal B 20 mg/kg,CON组和DM组给予同等剂量的柠檬酸盐缓冲剂.连续干预8周,采用Morris水迷宫试验测试实验动物的学习和记忆能力;用蛋白质免疫印迹试验(Western blotting)检测大鼠海马组织的突触可塑性相关蛋白突触素(SYN)、突触后致密蛋白95(PSD-95)表达水平.结果 Sal B治疗后,Sal B组大鼠血糖水平明显低于DM组(mmol/L:14.03±2.01比23.85±3.28,P<0.05),说明Sal B有降血糖作用.水迷宫试验测试结果显示,DM组大鼠逃避潜伏期长于CON组(s:49.23±4.15比23.48±2.78,P<0.05),穿台次数少于CON组(次:2.15±0.42比6.66±0.89,P<0.05),表明DM大鼠认知功能受损.Sal B治疗后大鼠的逃避潜伏期较DM组降低(s:33.63±3.21比49.23±4.15,P<0.05),穿台次数增加(次:4.55±0.77比2.15±0.42,P<0.05).Western blotting结果显示,DM组大鼠的突触可塑性相关蛋白SYN和PSD-95表达水平明显低于CON组〔SYN(SYN/β-actin):0.24±0.05比0.75±0.07,PSD-95(PSD-95/β-actin):0.15±0.02比0.68±0.09,均P<0.05〕;Sal B治疗后,SYN和PSD-95蛋白表达水平较DM组明显升高〔SYN(SYN/β-actin):0.61±0.09比0.24±0.05,PSD-95(PSD-95/β-actin):0.52±0.08比0.15±0.02,均P<0.05〕.结论 Sal B可改善DM大鼠的认知功能障碍,其机制可能与上调突触可塑性蛋白相关.

Objective To explore whether salvianolic acid B(Sal B)can improve learning and memory disorders in diabetes mellitus(DM)rats by regulating the expression levels of synaptic plasticity proteins.Methods Thirty male SD rats were randomly divided into 3 groups:normal control(CON,n=10),DM(n=10),and Sal B(n=10)groups.Intraperitoneal injection of streptozotocin(STZ)was used to establish DM model,and rats with blood glucose M 16.7 mmol/L were considered as the successful modeling.After modeling,the rats in Sal B group were intraperitoneally injected with Sal B(20 mg/kg),and CON group and DM groups were given the same dose of citrate buffer.After 8 weeks of treatment,Moms water maze test was used to test the learning and memory abilities of rats in experiment.Western Blotting was used to detect the expression levels of synaptic plasticity related proteins synaptophysin(SYN)and postsynaptic dense protein 95(PSD-95)in the rat hippocampus tissue.Results After Sal B treatment,the blood glucose level of rats in Sal B group was significantly lower than that in DM group(mmol/L:14.03±2.01 vs.23.85±3.28,P<0.05).The Morris water maze test showed that the escape incubation period in DM group was longer than that in CON group(seconds:49.23±4.15 vs.23.48±2.78,P<0.05),and the number of crossing was lower than that in CON group(times:2.15±0.42 vs.6.66±0.89,P<0.05),indicating that the cognitive function of DM rats was impaired.After Sal B treatment,the escape incubation period in Sal B group was lower than that in DM group(seconds:33.63±3.21 vs.49.23±4.15,P<0.05),and the number of crossing was increased(4.55±0.77 vs.2.15±0.42,P<0.05).Western blotting results showed that the plasticity related protein expression levels of SYN and PSD-95 in DM group were significantly lower than those in CON group[SYN(SYN/β-actin):0.24±0.05 vs.0.75±0.07,PSD-95(PSD-95/P-actin):0.15±0.02 vs.0.68±0.09,both P<0.05];after Sal B treatment,the plasticity related protein expression levels of SYN and PSD-95 in Sal B group were significantly higher than those of DM group[SYN(SYN/β-actin):0.61±0.09 vs.0.24±0.05,PSD-95(PSD-95/β-actin):0.52±0.08 vs.0.15±0.02,both P<0.05].Conclusion Sal B can improve cognitive dysfunction in DM rats,and its mechanism may be related to the up-regulation of synaptic plasticity proteins.