We aimed to investigate the exact effect of IL-17 on regulating neural stem cells (NSCs) stemness and adult neurogenesis in ischemic cortex after stroke, how Astragaloside IV(As-IV) regulated IL-17 expression and the underlying mechanism. Photochemical brain ischemia model was established and IL-17 protein expression was observed at different time after stroke in WT mice. At 3 days after stroke, when IL-17 expression peaked, IL-17 knock out (KO) mice were used to observe cell proliferation and neurogenesis in ischemic cortex. Then, As-IV was administered intravenously to assess cell apoptosis, proliferation, neurogenesis, and cognitive deficits by immunochemistry staining, western blots, and animal behavior tests in WT mice. Furthermore, IL-17 KO mice and As-IV were used simultaneously to evaluate the mechanism of cell apoptosis and proliferation after stroke in vivo. Besides, in vitro, As-IV and recombinant mouse IL-17A was administered, respectively, into NSCs culture, and then their diameters, viable cell proliferation and pathway relevant protein was assessed. The results showed knocking out IL-17 contributed to regulating PI3K/Akt pathway, promoting NSCs proliferation, and neurogenesis after ischemic stroke. Moreover, As-IV treatment helped inhibit neural apoptosis, promote the neurogenesis and eventually relieve mice anxiety after stroke. Unsurprisingly, IL-17 protein expression could be downregulated by As-IV in vivo and in vitro and they exerted antagonistic effect on neurogenesis by regulating Akt/GSK-3β pathway, with significant regulation for apoptosis. In conclusion, IL-17 exerts negative effect on promoting NSCs proliferation, neurogenesis and cognitive deficits after ischemic stroke, which could be reversed by As-IV.

我们的目的是研究IL-17对调节脑卒中后缺血皮质神经干细胞（NSC）干性和成体神经发生的确切作用，黄芪甲苷IV（As-IV）如何调节IL-17表达及其潜在机制。建立光化学脑缺血模型，观察WT小鼠脑卒中后不同时间IL-17蛋白表达。中风后3天，当IL-17表达达到峰值时，使用IL-17敲除（KO）小鼠观察缺血皮质中的细胞增殖和神经发生。然后，静脉注射 As-IV，通过免疫化学染色、蛋白质印迹和动物行为测试来评估 WT 小鼠的细胞凋亡、增殖、神经发生和认知缺陷。此外，同时使用IL-17 KO小鼠和As-IV来评估体内中风后细胞凋亡和增殖的机制。此外，在体外，将As-IV和重组小鼠IL-17A分别施用到NSCs培养物中，然后评估它们的直径、活细胞增殖和通路相关蛋白。结果显示，敲除IL-17有助于调节PI3K/Akt通路，促进NSCs增殖和缺血性中风后的神经发生。此外，As-IV治疗有助于抑制神经细胞凋亡，促进神经发生，最终缓解小鼠中风后的焦虑。不出所料，As-IV 在体内和体外均可下调 IL-17 蛋白表达，并通过调节 Akt/GSK-3β 通路对神经发生发挥拮抗作用，并对细胞凋亡具有显着调节作用。总之，IL-17 对促进缺血性中风后 NSC 增殖、神经发生和认知缺陷产生负面影响，而 As-IV 可以逆转这种负面影响。