手掌参对2型糖尿病认知障碍的作用及机制研究

Effect of Gymnadenia conopsea on rats with type 2 diabetes cognitive impairment and related mechanism

目的 观察手掌参对2型糖尿病认知障碍大鼠的影响,评价其神经保护作用并探讨其机制。方法 雄性SD大鼠,随机选取8只为空白组,以普通饲料喂养,其余均以自制高脂高糖饲料喂养30 d后腹腔注射链脲佐菌素(STZ)35 mg·kg^(-1),对照组注射等体积柠檬酸缓冲液。72 h后尾尖静脉取血检测空腹血糖,以空腹血糖≥16.7 mmol·L^(-1)视为糖尿病造模成功。造模成功后继续喂养60 d高脂高糖饲料,随后将大鼠随机分为模型组,二甲双胍组[0.2 g/(kg·d)],手掌参水提物低(PaGL)、中(PaGM)、高(PaGH)剂量组[0.6、1.2、2.4 g/(kg·d)],每组8只,给药30 d后Morris水迷宫法进行测试,结束后大鼠取血,检测大鼠血清中超氧化物歧化酶(SOD)活性和丙二醛(MDA)水平,HE染色观察海马组织病理改变,Western blot法检测海马组织中PI3K/Akt蛋白的表达。结果 与空白组相比,模型组大鼠血糖明显升高,体重显著下降,大鼠逃避潜伏期和游泳距离明显延长,目标象限的游泳时间和穿越站台的次数显著降低,海马神经元损伤严重,血清中SOD活性降低,MDA含量升高,PI3K/Akt蛋白表达水平明显降低;与模型组大鼠比较,手掌参可明显增加大鼠体重和降低空腹血糖,缩短大鼠逃避潜伏期和游泳距离,增加目标象限的游泳时间和穿越站台的次数,改善海马神经元损伤,提高SOD活性,降低MDA水平,升高PI3K/Akt蛋白表达水平。结论 手掌参可明显改变糖尿病大鼠的认知障碍,其机制可能与降低MDA水平、提高SOD的活性及调控PI3K/Akt通路有关。

Objective To determine the effect of Gymnadenia conopsea on rats with type 2 diabetes cognitive impairment,evaluate its neuroprotective effect and explore its mechanism.Methods Totally 8 male SD rats were randomly selected as a control group with ordinary diet.The rest of the rats were given homemade high-fat and high-sugar diet for 30 days and then intraperitoneally injected with streptozotocin 35 mg·kg^(-1).The control group was injected with an equal volume of citric acid buffer.After 72 hours,the blood was taken from the caudal vein to detect fasting blood glucose in major rats,and the fasting blood glucose≥16.7 mmol·L^(-1) was regarded as successful diabetes modeling.After successful modeling,the rats were fed high-fat diet for 60 days,and then the rats were randomly divided into a model group,a metformin group[0.2 g/(kg·d)],the Gymnadenia conopsea water extracts low,medium and high dose groups [0.6, 1.2, 2.4 g/ (kg·d)], 8 rats in each group. Morris water maze method was tested after 30 days of administration, and blood were taken after the test. Superoxide dismutase (SOD) activity and malondialdehyde (MDA) level in the rat serum were detected, the hippocampal histopathological changes were observed by HE staining, and PI3K/Akt protein expression in the hippocampal tissues was detected by Western blot. Results Compared with the blank group, the blood glucose increased obviously and body weight decreased in the model group, the rat escape latency and swimming distance prolonged, the swimming time and the number of platform crossing in the target quadrant reduced, severe hippocampal neuronal damaged, SOD activity decreased, MDA content increased, and the expression level of PI3K/Akt protein significantly decreased. Compared with the model rats, Gymnadenia conopsea significantly increased body weight, reduced fasting blood glucose, shortened the rat escape latency and swimming distance, increased the swimming time and number of platform crossing in the target quadrant, improved the hippocampal neuronal damage, improved SOD activity, reduced MDA level, and increased the expression level of PI3K/Akt protein. Conclusion Gymnadenia conopsea significantly improve cognitive impairment in diabetic rats, whose mechanism may be related to reducing MDA level, increasing SOD activity and regulating PI3K/Akt pathway.