Puerarin protects rat brain against ischemia/reperfusion injury by suppressing autophagy via the AMPK-mT OR-ULK1 signaling pathway

Puerarin suppresses autophagy to alleviate cerebral ischemia/reperfusion injury, and accumulating evidence indicates that the AMPKm TOR signaling pathway regulates the activation of the autophagy pathway through the coordinated phosphorylation of ULK1. In this study, we investigated the mechanisms underlying the neuroprotective effect of puerarin and its role in modulating autophagy via the AMPK-m TOR-ULK1 signaling pathway in the rat middle cerebral artery occlusion model of cerebral ischemia/reperfusion injury. Rats were intraperitoneally injected with puerarin, 50 or 100 mg/kg, daily for 7 days. Then, 30 minutes after the final administration, rats were subjected to transient middle cerebral artery occlusion for 90 minutes. Then, after 24 hours of reperfusion, the Longa score and infarct volume were evaluated in each group. Autophagosome formation was observed by transmission electron microscopy. LC3, Beclin-1 p62, AMPK, m TOR and ULK1 protein expression levels were examined by immunofluorescence and western blot assay. Puerarin substantially reduced the Longa score and infarct volume, and it lessened autophagosome formation in the hippocampal CA1 area following cerebral ischemia/reperfusion injury in a dose-dependent manner. Pretreatment with puerarin（50 or 100 mg/kg） reduced Beclin-1 expression and the LC3-II/LC3-I ratio, as well as p-AMPK and p S317-ULK1 levels. In comparison, it increased p62 expression. Furthermore, puerarin at 100 mg/kg dramatically increased the levels of p-m TOR and p S757-ULK1 in the hippocampus on the ischemic side. Our findings suggest that puerarin alleviates autophagy by activating the APMK-m TOR-ULK1 signaling pathway. Thus, puerarin might have therapeutic potential for treating cerebral ischemia/reperfusion injury.

Fermented Chinese formula Shuan-Tong-Ling attenuates ischemic stroke by inhibiting inflammation and apoptosis

The fermented Chinese formula Shuan-Tong-Ling is composed of radix puerariae（Gegen）,salvia miltiorrhiza（Danshen）,radix curcuma（Jianghuang）,hawthorn（Shanzha）,salvia chinensis（Shijianchuan）,sinapis alba（Baijiezi）,astragalus（Huangqi）,panax japonicas（Zhujieshen）,atractylodes macrocephala koidz（Baizhu）,radix paeoniae alba（Baishao）,bupleurum（Chaihu）,chrysanthemum（Juhua）,rhizoma cyperi（Xiangfu） and gastrodin（Tianma）,whose aqueous extract was fermented with lactobacillus,bacillus aceticus and saccharomycetes.ShuanTong-Ling is a formula used to treat brain diseases including ischemic stroke,migraine,and vascular dementia.Shuan-Tong-Ling attenuated H_2O_2-induced oxidative stress in rat microvascular endothelial cells.However,the potential mechanism involved in these effects is poorly understood.Rats were intragastrically treated with 5.7 or 17.2 m L/kg Shuan-Tong-Ling for 7 days before middle cerebral artery occlusion was induced.The results indicated Shuan-Tong-Ling had a cerebral protective effect by reducing infarct volume and increasing neurological scores.Shuan-Tong-Ling also decreased tumor necrosis factor-α and interleukin-1β levels in the hippocampus on the ischemic side.In addition,Shuan-Tong-Ling upregulated the expression of SIRT1 and Bcl-2 and downregulated the expression of acetylated-protein 53 and Bax.Injection of 5 mg/kg silent information regulator 1（SIRT1） inhibitor EX527 into the subarachnoid space once every 2 days,four times,reversed the above changes.These results demonstrate that Shuan-Tong-Ling might benefit cerebral ischemia/reperfusion injury by reducing inflammation and apoptosis through activation of the SIRT1 signaling pathway.

Leukemia Inhibitory Factor Decreases Neurogenesis and Angiogenesis in a Rat Model of Intracerebral Hemorrhage

Neurogenesis and angiogenesis can improve the neurologic function after intracerebral hemorrhage(ICH).Leukemia inhibitory factor(LIF)plays an important role in neurogenesis and angiogenesis.In this study,a rat model of autologous blood-induced ICH was used to evaluate the effect of LIF on the neurogenesis and angiogenesis following ICH.After ICH,LIF-positive neurons and dilated vessels were detected in the peri-hematomal region.It was found that LIF levels increased significantly and peaked 14 days after ICH induction.Double immunofluorescence confirmed that LIF was expressed in neurons and endothelial cells.ICH also led to increases of doublecortin(DCX)-and von Willebrand factor(vWF)-positive cells as well as proliferation of cell nuclear antigen(PCNA)+/DCX+and PCNA+/vWF+nuclei.All these ICH-induced increases were significantly attenuated by exogenous LIF in fusion.These data suggested that LIF was a negative regulator of neurogenesis and angiogenesis after ICH.