目的 探討柴胡皂苷A對腦外傷大鼠腺苷酸活化蛋白激酶（AMPK）–雷帕毒素靶蛋白復(fù)合物1（mTORC1）信號通路及海馬神經(jīng)元自噬的影響。方法 60只SD大鼠隨機(jī)分為假手術(shù)組、模型組及柴胡皂苷A低劑量（5 mg/kg）、中劑量（10 mg/kg）、高劑量（20 mg/kg）組，和陽性對照（自噬抑制劑3-甲基腺嘌呤，15 mg/kg）組，每組10只。除假手術(shù)組外，其余各組大鼠均采用皮質(zhì)撞擊法構(gòu)建腦外傷大鼠模型，造模成功后，柴胡皂苷A各劑量組、陽性對照組ip相應(yīng)藥物，假手術(shù)組和模型組ip等量生理鹽水，持續(xù)14 d。采用Morris水迷宮測定大鼠的認(rèn)知功能，以蘇木精-伊紅染色檢測各組大鼠海馬組織病理變化，采用酶聯(lián)免疫吸附試劑盒檢測大鼠海馬組織腦源性神經(jīng)生長因子（BDNF）、白細(xì)胞介素-6（IL-6）、腫瘤壞死因子（TNF-α）水平。透射電鏡觀察海馬組織自噬情況，采用蛋白免疫印跡法檢測海馬組織中微管相關(guān)蛋白1輕鏈3（LC3）、Beclin-1及AMPK-mTORC1相關(guān)通路蛋白表達(dá)。結(jié)果 與假手術(shù)組相比，模型組大鼠的潛伏期顯著延長，穿臺次數(shù)顯著降低，海馬組織神經(jīng)細(xì)胞損壞嚴(yán)重，呈現(xiàn)細(xì)胞破裂、細(xì)胞核固縮等狀態(tài)，海馬組織BDNF含量顯著降低，IL-6、TNF-α表達(dá)顯著升高，海馬組織自噬小泡、LC3Ⅱ/LC3Ⅰ、Beclin-1、p-AMPK/AMPK蛋白表達(dá)水平顯著升高，p-mTORC1/mTORC1表達(dá)水平顯著下降。與模型組相比，柴胡皂苷A各劑量組的潛伏期呈現(xiàn)逐漸縮短的趨勢，穿臺次數(shù)呈現(xiàn)逐漸升高的趨勢，BDNF含量顯著升高，IL-6、TNF-α表達(dá)顯著降低，海馬組織自噬小泡、LC3Ⅱ/LC3Ⅰ、Beclin-1、p-AMPK/AMPK蛋白表達(dá)水平顯著降低，p-mTORC1/mTORC1表達(dá)水平顯著升高，且均呈現(xiàn)一定的劑量相關(guān)性。結(jié)論 柴胡皂苷A可調(diào)節(jié)腦外傷大鼠海馬神經(jīng)元自噬情況，可能通過抑制AMPK，促進(jìn)mTORC1表達(dá)實(shí)現(xiàn)。

Objective To investigate the effects of saikosaponin A on the signal pathway of AMPK-mTORC1, and autophagy of hippocampal neurons in rats with traumatic brain injury.Methods A total of 60 SD rats were randomly divided into sham operation group, model group, saikosaponin A low-dose group (5 mg/kg), medium-dose group (10 mg/kg), and high-dose group (20 mg/kg), positive control group (autophagy inhibitor 3-methyladenine, 15 mg/kg), with 10 rats in each group. Except for the sham operation group, the rats in other groups were established with cortical impact method, and after successful modeling, saikosaponin A groups and positive control group were intraperitoneally injected with corresponding drugs, while the sham operation group and model group were injected with the same amount of normal saline for 14 d. Morris water maze was used to measure the cognitive function of rats, hematoxylin-eosin staining was used to detect the pathological changes of hippocampus, enzyme-linked immunosorbent assay was used to detect the levels of BDNF, IL-6, and TNF-α. Observation of autophagy of hippocampus by transmission electron microscopy, and LC3, Beclin-1, and AMPK-mTORC1 related pathway proteins in hippocampus were detected by Western blotting.Results Compared with sham operation group, the latency of rats in the model group was significantly extended, the times of crossing the platform was significantly lower, hippocampal neurons were seriously damaged, showing cell rupture and nuclear pyknosis, the content of BDNF in hippocampus was significantly decreased, the expression of IL-6 and TNF-α was significantly increased, autophagic vesicles and the protein expression levels of LC3Ⅱ/LC3Ⅰ, Beclin-1, and p-AMPK/AMPK in hippocampus were significantly increased, but the expression level of p-mTORC1/mTORC1 was significantly decreased. Compared with those in the model group, the latency of rats in saikosaponin A groups decreased gradually, the times of crossing the platform gradually increased, the content of BDNF in hippocampus increased gradually, the expression of IL-6 and TNF-α decreased gradually, autophagic vesicles and the protein expression levels of LC3Ⅱ/LC3Ⅰ, Beclin-1 and p-AMPK/AMPK in hippocampus decreased gradually, the expression level of p-mTORC1/mTORC1 increased gradually, and there was a dose-dependent manner.Conclusion Saikosaponin A can regulate the autophagy of hippocampal neurons in rats with traumatic brain injury, which may be achieved by inhibiting AMPK and promoting the expression of mTORC1.

R965

河南省科技發(fā)展計(jì)劃項(xiàng)目（1821023111069）