中药复方益糖康对db/db小鼠认知障碍的改善及铁死亡的作用＊

目的 探讨中药复方益糖康对db/db小鼠认知缺陷的改善以及可能的机制。方法 选取24只db/db小鼠和8只db/m小鼠,随机分为四组：正常对照组（db/m组）、模型组（db/db组）、益糖康组（YTK组）以及西药（选用利拉鲁肽Liraglutide）对照组（LIRA组）。首先对小鼠空腹血糖（FBG）、血清胰岛素水平（FINS）和胰岛素抵抗指数（HOMA-RI）进行观察;通过Morris水迷宫任务和旷场实验对小鼠进行行为学检测;采用Nissl染色观察海马神经元Nissl小体数量,western blot检测突触后致密物质95（PSD 95）、突触素（SYN）以及脑源性神经营养因子（BDNF）蛋白观察海马的突触可塑性;通过透射电镜观察线粒体超微形态,免疫双标共染Cox1/Cox4观察线粒体功能变化,同时免疫荧光和western blot检测海马GPX 4、SLC7A11及Nrf 2蛋白的表达观察铁死亡。结果 与db/m组相比,db/db组小鼠FBG、FINS和HOMA-RI明显升高;水迷宫和旷场实验等行为学功能显著下降,Nissl小体形态及数量异常,同时PSD 95、SYN及BDNF蛋白表达量明显降低;海马神经元线粒体结构异常,Cox1、GPX 4、SLC7A11及Nrf 2表达明显下降,Cox4表达上升。与db/db组相比,LIRA组及YTK组FBG、FINS和HOMA-RI明显下降;两组水迷宫均有明显改善,YTK组旷场实验改善更为明显,同时两组小鼠Nissl小体及PSD 95、SYN和BDNF蛋白表达均有回升;两组小鼠海马神经元线粒体结构均有改善,Cox1、GPX 4、SLC7A11及表达明显上升,Cox4表达下降,YTK组Nrf 2表达升高,但LIRA组Nrf 2表达无统计学意义。结论 中药复方益糖康可以改善神经和突触可塑性损伤,保护认知功能,其机制可能是通过上调Nrf 2提高SLC7A11和GPX 4表达,改善线粒体结构和功能,抑制铁死亡。

Effects of Yitangkang Formula on Cognitive Impairment and Ferroptosis in db/db Mice

Objective To investigate whether the Chinese herbal formula Yitangkang could improve cognitive deficits and possible mechanisms in db/db mice.Methods 24 db/db mice and 8 db/m mice were divided into normal group (db/m), model group (db/db), Yitangkang group (YTK) and Liraglutide group (LIRA). First, the mice were examined for fasting blood glucose (FBG), serum insulin (FINS) levels and Homeostasis model assessment-insulin resistance index (HOMA-RI); The Morris water maze test and open field test were used to behaviorally examine the mice; Synaptic plasticity and neuronal morphology in the hippocampus were observed by Nissl staining and PSD 95, SYN, and BDNF protein were detected by western blot; Mitochondrial ultrastructure was assessed by transmission electron microscopy; Cox1/Cox4 was co-stained by immunofluorescence, while the hippocampal expression of GPX 4, SLC7A11, and Nrf 2 were examined by immunofluorescence and western blot to detect ferroptosis.Results Compared with the db/m group, the FBG, FINS and HOMA-RI in the db/db mice were significantly increased; The functions of water maze test and open field test were significantly decreased; The morphology and quantity of Nissl body were abnormal; The expression of PSD 95, SYN and BDNF proteins decreased significantly; The mitochondrial structure of hippocampal neurons was damaged; The expressions of Cox1, GPX 4, SLC7A11 and Nrf 2 decreased significantly, with the expression of Cox4 increased. Compared with the db/db group, the FBG, FINS and HOMA-RI of the LIRA group and YTK group were significantly decreased; The water maze test for these two groups was significantly improved; The open field test for the YTK group improved more significantly; The number of Nissl body and the expressions of PSD 95, SYN and BDNF proteins increased; The mitochondrial structure of hippocampal neurons in the two groups of mice improved; The expression of Cox1, GPX 4 and SLC7A11 increased significantly, and the expression of Cox4 decreased. The expression of Nrf 2 protein in the YTK group increased, but the expression of Nrf 2 in the LIRA group was not statistically significant.Conclusion Yitangkang formula can improve nerve and synaptic plasticity damage and protect cognitive function. The mechanism may be through upregulation of Nrf 2 to increase the expression of SLC7A11 and GPX 4, improve mitochondrial structure and function, and inhibit ferroptosis.