Effect of puerarin on regulation of AMPK-mTOR signaling pathway to inhibit autophagy and alleviate focal cerebral ischemia reperfusion injury / 中草药

ABSTRACT

Objective: To investigate the effect of puerarin on the regulation of AMPK-mTOR signaling pathway to inhibit autophagy and alleviate focal cerebral ischemia reperfusion injury. Methods: Forty male Sprague-Dawley rats were randomly divided into four groups Sham group, model group, puerarin low-dose (50 mg/kg) group and puerarin high-dose (100 mg/kg) group. Pretreatment with puerarin for 7 d, then the middle cerebral artery occlusion (MCAO) model was established 0.5 h after the last administration according to Longa’s method. After 1.5 h of ischemia and 24 h of reperfusion, the neurological deficit scores were assessed, the infarct volume was calculated by TTC staining. The formation of autophagosome was observed by electron microscopy. The expression levels of LC3, p62, AMPK, p-AMPK, mTOR, p-mTOR, Ulk1, and pS757-Ulk1 were detected by Western blotting. Results: Compared with the Sham group, the neurological deficit scores and infarct volume in model group were significantly increased, the numbers of autophagosome increased, and the rate of LC3-II/LC3-I significantly increased, the expression level of p62 gradually decreased. The expression of p-AMPK was markedly up-regulated, while the expression of p-mTOR and pS757-Ulk1 was significantly down-regulated. Compared with the model group, the neurological deficit scores and infarct volume were significantly reduced, the number of autophagosome and the rate of LC3-II/LC3-I decreased, the expression of p62 was significantly up-regulated, the expression of p-AMPK was markedly down-regulated, the levels of p-mTOR and pS757-Ulk1 were significantly up-regulated. Conclusion: Puerarin alleviates cerebral ischemia-reperfusion injury may through suppressing autophagy via the AMPK-mTOR-Ulk1 signaling pathway.