查看更多>>摘要:目的 评价抑癌因子蛋白磷酸酶2A(CIP2A)在术前睡眠剥夺加重老龄小鼠术后认知功能障碍中的作用。 方法 SPF级健康C57BL/6J小鼠110只,雌雄不拘,18~20月龄,体质量29~35 g。采用随机数字表法分为5组(n=22):假手术组(S组)、腹部手术组(O组)、术前睡眠剥夺+腹部手术组(D+O组)、CIP2A shRNA+腹部手术组(CS+O组)和CIP2A shRNA+术前睡眠剥夺+腹部手术组(CS+D+O组)。术前14 d时,S组、O组和CS+O组海马注射对照shRNA慢病毒,D+O组和CS+D+O组海马注射CIP2A shRNA慢病毒。术前连续3 d行睡眠剥夺。术后7~11 d采用Morris水迷宫实验评估认知功能。术后3 d时深麻醉下处死小鼠取海马,采用Western blot法测定CIP2A、高迁移率族蛋白B1(HMGB1)、离子化钙结合适配蛋白-1(Iba-1)、蛋白磷酸酶2A的α亚单位(PP2Aa)、蛋白磷酸酶2A的催化亚单位(PP2Ac)、磷酸化tau蛋白(p-tau) (S396)和p-tau (S404)表达,检测海马ROS、MDA和SOD的水平,免疫荧光染色法计数海马CA1区Iba-1阳性细胞。 结果 与S组比较,O组逃避潜伏期延长,穿越平台位置次数减少,目标象限停留时间缩短,海马CIP2A、Iba-1和HMGB1表达上调,PP2Ac表达下调,ROS、MDA水平和Iba-1阳性细胞计数升高,SOD活性降低(P<0.05);与O组比较,D+O组逃避潜伏期延长,穿越平台位置次数减少,目标象限停留时间缩短,海马CIP2A、Iba-1和HMGB1表达上调,PP2Ac表达下调,ROS、MDA水平和Iba-1阳性细胞计数升高,SOD水平降低,CS+O组逃避潜伏期缩短,穿越平台位置次数增加,目标象限停留时间延长,海马CIP2A、Iba-1和HMGB1表达下调,PP2Ac表达上调,ROS、MDA水平和Iba-1阳性细胞计数降低,SOD活性升高(P<0.05);与D+O组比较,CS+D+O组逃避潜伏期缩短,穿越平台位置次数增加,目标象限停留时间延长,海马CIP2A、Iba-1和HMGB1表达下调,PP2Ac表达上调,ROS、MDA水平和Iba-1阳性细胞计数降低,SOD水平升高(P<0.05)。5组海马PP2Aa表达比较差异无统计学意义(P>0.05)。 结论 术前睡眠剥夺加重老龄小鼠术后认知功能障碍的机制与上调CIP2A的表达,促进氧化应激反应、神经炎症反应以及tau蛋白磷酸化有关。 Objective To evaluate the role of cancerous inhibitor of protein phosphatase 2A (CIP2A) in preoperative sleep deprivation (PSD)-induced aggravation of postoperative cognitive dysfunction (POCD) in aged mice. Methods One hundred and ten healthy C57BL/6J mice of either sex, aged 18-20 months, weighing 29-35 g, were divided into 5 groups (n=22 each) using a random number table method: sham operation group (S group), abdominal surgery group (O group), PSD + abdominal surgery group (D+ O group), CIP2A shRNA + abdominal surgery group (CS+ O group), and CIP2A shRNA+ PSD+ abdominal surgery group (CS+ D+ O group). At 14 days before surgery, control shRNA lentivirus was injected into the hippocampus in S, O and CS+ O groups, and CIP2A shRNA was injected into the hippocampus in D+ O and CS+ D+ O groups. PSD was carried out for 3 consecutive days prior to surgery. Cognitive function was assessed using the Morris water maze test at days 7-11 after surgery. The mice were sacrificed under deep anesthesia at day 3 after surgery, and hippocampal tissues were obtained to determine the expression of CIP2A, high mobility group box 1 (HMGB1), ionized calcium-binding adapter molecule 1 (Iba-1), alpha subunit of protein phosphatase 2A (PP2Aa), catalytic subunit of protein phosphatase 2A (PP2Ac), phosphorylated tau protein (p-tau) (S396), and p-tau (S404) (by Western blot), levels of reactive oxygen species (ROS), malondialdehyde (MDA), and superoxide dismutase (SOD), and count of Iba-1 positive cells in the hippocampal CA1 region (using immunofluorescence staining). Results Compared with S group, the escape latency was significantly prolonged, the frequency of crossing the platform was reduced, duration of stay in the target quadrant was shortened, the expression of CIP2A, Iba-1 and HMGB1 was up-regulated, PP2Ac expression was down-regulated, levels of ROS and MDA and count of Iba-1 positive cells were increased, and the activity of SOD was decreased in O group (P<0.05). Compared with O group, the escape latency was significantly prolonged, the frequency of crossing the platform was reduced, duration of stay in the target quadrant was shortened, the expression of CIP2A, Iba-1 and HMGB1 was up-regulated, PP2Ac expression was down-regulated, levels of ROS and MDA and count of Iba-1 positive cells were increased, and the activity of SOD was decreased in D+ O group, and the escape latency was significantly shortened, the frequency of crossing the platform was increased, duration of stay in the target quadrant was prolonged, the expression of CIP2A, Iba-1 and HMGB1 was down-regulated, PP2Ac expression was up-regulated, levels of ROS and MDA and count of Iba-1 positive cells were decreased, and the activity of SOD was increased in CS+ O group (P<0.05). Compared with D+ O group, the escape latency was significantly shortened, the frequency of crossing the platform was increased, duration of stay in the target quadrant was prolonged, the expression of CIP2A, Iba-1 and HMGB1 was down-regulated, PP2Ac expression was up-regulated, levels of ROS and MDA and count of Iba-1 positive cells were decreased, and the activity of SOD was increased in CS+ D+ O group (P<0.05). There was no significant difference in PP2Aa expression among the five groups (P>0.05). Conclusions The mechanism by which PSD aggravates POCD is related to up-regulating the expression of CIP2A and promoting oxidative stress responses, neuroinflammatory responses and phosphorylation of tau protein in aged mice.