五味子木脂素改善衰老小鼠学习记忆能力的机制

目的:研究五味子木脂素(Schisandrae Chinensis Fructus lignans,SCL)对D-半乳糖(D-galactose,D-gal)所致衰老模型小鼠学习记忆能力的改善作用。方法:ICR小鼠随机分为4组,即正常组(灌胃蒸馏水,皮下注射生理盐水),模型组(灌胃蒸馏水,皮下注射200 mg·kg^-1·d^-1D-gal),吡拉西坦组(灌胃吡拉西坦200 mg·kg^-1·d^-1,皮下注射D-gal 200 mg·kg^-1·d^-1),SCL低剂量组(灌胃SCL 50 mg·kg^-1·d^-1,皮下注射D-gal 200 mg·kg^-1·d^-1),SCL中剂量组(灌胃SCL 100 mg·kg^-1·d^-1,皮下注射D-gal200 mg·kg^-1·d^-1),SCL高剂量组(灌胃SCL 200 mg·kg^-1·d^-1,皮下注射D-gal 200 mg·kg^-1·d^-1),连续给药10周;通过避暗实验及Morris水迷宫实验观察SCL对D-gal致衰老模型小鼠学习记忆能力的影响;通过化学比色法检测小鼠脑组织中超氧化物歧化酶(superoxide dismutase,SOD)活力及丙二醛(malondialdehyde,MDA)含量;通过聚合酶链式反应(polymerase chain reaction,PCR)检测小鼠脑组织中过氧化物还原酶-6(peroxiredoxin-6,Prdx6),谷胱甘肽过氧化酶1(glutathione peroxidase 1,GSH-Px1)mRNA表达情况;蛋白免疫印迹法(Western blot)检测小鼠组织中Prdx6,GSH-Px1蛋白表达情况。结果:行为学实验中,与正常组比较,模型组小鼠避暗错误次数明显增加(P<0.05),潜伏期显著减少(P<0.01),小鼠穿台次数和目标象限停留时间显著减少(P<0.01),可作为建模成功的指标。与模型组比较,吡拉西坦组,SCL中、高剂量组小鼠避暗错误次数明显减少(P<0.05,P<0.01),潜伏期明显延长(P<0.05,P<0.01),同时,SCL高剂量组小鼠水迷宫穿台次数和目标象限停留时间显著增加(P<0.01)。与正常组比较,模型组小鼠脑组织中的SOD活力显著降低(P<0.01),MDA含量增加(P<0.05),Prdx6,GSH-Px1mRNA及蛋白表达量明显下降(P<0.05,P<0.01)。与模型组比较,吡拉西坦组,SCL低、中、高剂量组小鼠脑组织中SOD活力增高(P<0.05),MDA水平降低(P<0.05),Prdx6,GSH-Px1 mRNA及蛋白的表达水平显著升高(P<0.05,P<0.01),说明SCL给药组具有剂量依赖性。结论:SCL能改善D-gal致衰老模型小鼠学习记忆能力,该作用可能与SCL提高小鼠抗氧化能力及上调小鼠脑组织中Prdx6,GSH-Px1的表达水平有关。

Mechanism of Schisandrae Chinensis Fructus Lignans in Alleviating Learning and Memory Ability in D-galactose Aging Mice

Objective:To study the effect of Schisandrae Chinensis Fructus lignans(SCL)on learning and memory ability of D-galactose(D-gal)-induced aging model mice.Method:ICR mice were randomly divided into 4 groups:normal group(distilled water,subcutaneous injection with normal saline),model group(distilled water,subcutaneous injection with 200 mg·kg^-1 D-gal),piracetam group(oral administration with 200 mg·kg^-1 piracetam,subcutaneous injection with 200 mg·kg^-1 D-gal),low-dose SCL group(oral administration with 50 mg·kg^-1·d^-1 SCL,subcutaneous injection with 200 mg·kg^-1·d^-1 D-gal),medium-dose SCL group(oral administration with 100 mg·kg^-1·d^-1 SCL,subcutaneous injection with 200 mg·kg^-1·d^-1 D-gal),high-dose SCL group(oral administration with 200 mg·kg^-1·d^-1 SCL,subcutaneous injection with 200 mg·kg^-1·d^-1 D-gal).The drugs were administered continuously for 10 weeks.Dark test and Morris water maze test were performed to observe the effect of SCL on the learning and memory ability of D-gal-induced aging mice.The activities of superoxide dismutase(SOD)and malondialdehyde(MDA)in mouse brain tissue were detected by chemical colorimetry.The expressions of peroxiredoxin-6(Prdx6)and glutathione peroxidase 1(GSH-Px1)mRNA in mouse brain tissue were detected by polymerase chain reaction(PCR).The expressions of Prdx6 and GSH-Px1 protein in mouse tissues were detected by Western blot.Result:In behavioral experiments,compared with normal group,the number of dark avoidance errors in model group significantly increased(P<0.05),the latency was significantly reduced(P<0.01),and the number of mouse passes and the target quadrant residence time were significantly reduced(P<0.01),which can be used as an indicator of successful modeling.Compared with the model group,the number of errors in the piracetam group,and medium and high-dose SCL groups was significantly reduced(P<0.05,P<0.01),and the latency was significantly prolonged(P<0.05,P<0.01).At the same time,the number of water maze passes and the target quadrant retention time in the high-dose SCL group increased significantly(P<0.01).The results of biochemical indicators showed that compared with normal group,the SOD activity in brain tissue of model group mice was significantly reduced(P<0.01),while the MDA content was increased(P<0.05).Compared with the model group,SOD activity in the brain tissues of piracetam group,and low,medium and high-dose piracetam groups was significantly increased(P<0.05),whereas the level of MDA was reduced(P<0.05).The expressions of Prdx6 and GSH-Px1 were significantly increased(P<0.05,P<0.01),indicating that the SCL administration group was dose-dependent.Conclusion:SCL can improve the learning and memory ability of D-gal-induced aging mice,which may be related to the antioxidation ability of SCL and the up-regulation of Prdx6 and GSH-Px1 expressions in mouse brain tissue.