硫化氢对糖尿病大鼠空间学习记忆和海马组织氧化应激的影响

Effects of hydrogen sulfide on spatial learning and memory and oxidative stress in hippocampus tissue of diabetic rat

目的:观察硫化氢(H2S)对糖尿病大鼠空间学习记忆的影响,并探讨其机制。方法:雄性SD大鼠随机分为正常(CON)组、糖尿病(STZ)组、糖尿病+硫氢化钠(NaHS)组(SH组)和正常+NaHS(CH)组,每组8只。采用一次性腹腔注射链脲佐菌素的方法制备1型糖尿病大鼠模型。造模成功4周后,SH组和CH组大鼠每天腹腔注射NaHS溶液56μmol/kg。处理4周后,测定大鼠空腹血糖(FBG)和体质量(BW);利用Morris水迷宫测试各组大鼠的空间学习记忆能力(逃避潜伏期、正确象限停留时间和到达正确象限的潜伏期);HE染色观察海马组织病理结构改变;利用试剂盒检测海马组织总抗氧化能力(TAOC)、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)和丙二醛(MDA)水平;实时荧光定量聚合酶链式反应检测海马组织核因子E2相关因子2(Nrf2)和血红素氧化酶1(HO-1) mRNA表达情况。结果:与CON组比较,CH组各项指标差异均无统计学意义(P> 0. 05);STZ组逃避潜伏期和到达正确象限的潜伏期延长,在正确象限停留时间缩短,大鼠海马组织病理结构损伤明显,FBG和MDA含量增加,BW、T-AOC、SOD、GSH-Px活性和Nrf2、HO-1 mRNA表达下降,差异均有统计学意义(P <0. 01)。与STZ组比较,除FBG外,SH组中以上各项指标均明显改善,差异均有统计学意义(P <0. 05~P <0. 01)。结论:H2S可以改善糖尿病大鼠的认知功能障碍,其机制可能与抑制海马组织氧化应激损伤、上调Nrf2/HO-1通路的表达相关。

Objective:To investigate the effects of hydrogen sulfide(H 2S)on spatial learning and memory in diabetic rats,and explore the underlying mechanism.Methods:Male rats were randomly divided into normal(CON)group,diabetes mellitus(STZ)group,diabetes+sodium hydrosulfide(NaHS)(SH)group,and normal+NaHS(CH)group,with 8 rats in each group.Type 1 diabetes was induced by a single intraperitoneal injection of streptozotocin.Four weeks after successfully making the model,rats in SH group and CH group were intraperitoneally injected with 56μmol/kg NaHS solution once a day.After treatment for 4 weeks,the fasting blood glucose(FBG)and body weight(BW)were measured.Spatial learning and memory abilities including escape latency,time spent in the target quadrant,and escape latency to the target quadrant were assessed by Morris water maze.The morphology of hippocampus tissue was observed by HE staining.The levels of total antioxidant capacity(T-AOC),superoxide dismutase(SOD),glutathione peroxidase(GSH-Px)and malondialdehyde(MDA)in hippocampus tissue were determined by the kits.The mRNA expression of nuclear factor erythroid 2-related factor 2(Nrf2)and heme oxygenase-1(HO-1)in hippocampus tissue were detected using real time-quantitative polymerase chain reaction.Results:Compared with the CON group,there was no significant difference in the various indexes in the CH group(P>0.05).In the STZ group,the escape latency and escape latency to the target quadrant were extended,and the time spent in the target quadrant was shortened(P<0.01).The histological structure of hippocampus tissue was obviously damaged.The levels of FBG and MDA were increased(P<0.01),whereas BW,the levels of T-AOC,SOD,GSH-Px activity,and Nrf2,HO-1 mRNA expression were decreased,the difference of which was statistically significant(P<0.01).Compared with the STZ group,except for FBG,the above indicators were markedly improved in the SH group(P<0.05 to P<0.01).Conclusions:H 2S attenuates cognitive dysfunction in diabetic rats,the mechanism of which might be associated with the inhibition of oxidative stress and up-regulation of the Nrf2/HO-1 pathway in hippocampus tissue.