缺氧缺血性脑损伤(HIBD)后,认知功能下降;然而,对于新生儿这种情况,没有有效的治疗策略。本研究旨在使用已建立的出生后第7天的HIBD模型评估分化簇200(CD200)/CD200R1轴在HIBD后认知功能中的作用。进行蛋白质印迹分析以评估CD200,CD200R1,与PI3K/Akt-NF-κB途径相关的蛋白质的表达水平,和炎症因子如TNF-α,IL-1β,和海马中的IL-6。此外,双免疫荧光标记用于评估海马中的M1小胶质细胞极化和神经发生。评价实验大鼠的学习记忆功能,进行了Morris水迷宫(MWM)试验。HIBD导致新生大鼠海马中CD200和CD200R1蛋白的表达减少,同时增加TNF-α的表达,IL-6和IL-1β蛋白,最终导致认知障碍。CD200Fc的给药,发现CD200的融合蛋白可增强p-PI3K和p-Akt的表达,但降低了p-NF-κB的表达。此外,CD200Fc抑制小胶质细胞M1极化,减少神经炎症,改善海马神经发生,减轻新生大鼠HIBD引起的认知障碍。相比之下,阻断CD200和CD200R1与抗CD200R1抗体(CD200R1Ab)之间的相互作用发挥相反的作用。此外,PI3K特异性激活剂,740Y-P,显著增加p-PI3K和p-Akt的表达,但降低了p-NF-κB的表达。它还抑制了小胶质细胞的M1极化,减少神经炎症,改善HIBD新生大鼠海马神经发生和认知功能。我们的研究结果表明,CD200/CD200R1轴的激活通过PI3K/Akt信号通路抑制NF-κB介导的小胶质细胞M1极化,改善HIBD诱导的认知障碍和海马神经发生障碍。
Following hypoxic-ischemic brain damage (HIBD), there is a decline in cognitive function; however, there are no effective treatment strategies for this condition in neonates. This study aimed to evaluate the role of the cluster of differentiation 200 (
CD200)/CD200R1 axis in cognitive function following HIBD using an established model of HIBD in postnatal day 7 rats. Western blotting analysis was conducted to evaluate the protein expression levels of
CD200, CD200R1, proteins associated with the PI3K/Akt-NF-κB pathway, and inflammatory factors such as TNF-α, IL-1β, and IL-6 in the hippocampus. Additionally, double-immunofluorescence labeling was utilized to evaluate M1 microglial polarization and neurogenesis in the hippocampus. To assess the learning and memory function of the experimental rats, the Morris water maze (MWM) test was conducted. HIBDleads to a decrease in the expression of
CD200 and CD200R1 proteins in the neonatal rat hippocampus, while simultaneously increasing the expression of TNF-α, IL-6, and IL-1β proteins, ultimately resulting in cognitive impairment. The administration of CD200Fc, a fusion protein of
CD200, was found to enhance the expression of p-PI3K and p-Akt, but reduce the expression of p-NF-κB. Additionally, CD200Fc inhibited M1 polarization of microglia, reduced neuroinflammation, improved hippocampal neurogenesis, and mitigated cognitive impairment caused by HIBD in neonatal rats. In contrast, blocking the interaction between
CD200 and CD200R1 with the anti-CD200R1 antibody (CD200R1 Ab) exerted the opposite effect. Furthermore, the PI3K specific activator, 740Y-P, significantly increased the expression of p-PI3K and p-Akt, but reduced p-NF-κB expression. It also inhibited M1 polarization of microglia, reduced neuroinflammation, and improved hippocampal neurogenesis and cognitive function in neonatal rats with HIBD. Our findings illustrate that activation of the CD200/CD200R1 axis inhibits the NF-κB-mediated M1 polarization of microglia to improve HIBD-induced cognitive impairment and hippocampal neurogenesis disorder via the PI3K/Akt signaling pathway.