Role of CIP2A in preoperative sleep deprivation-induced aggravation of postoperative cognitive dysfunction in aged mice / 中华麻醉学杂志

ABSTRACT

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.