Effect of nimodipine on activity of calcineurin in hippocampus of aged rats / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the effect of nimodipine on the activity of calcineurin (CaN) in the hippocampus of aged rats.Methods Sixty healthy male Sprague-Dawley rats,aged 18 months,weighing 550-650 g,were divided into 2 groups (n=30 each) using a random number tablesurgery group (group S) and nimodipine group (group N).Nimodipine 1 mg/kg was intraperitoneally injected in group N,while the cqual volume of normal saline was given instead in group S,and 30 min later exploratory laparotomy was performed.Ten rats in each group were randomly selected on 1 day before operation and 3 and 7 days after operation,and Morris water maze test was performed.After the end of Morris water maze test,10 rats were selected and sacrificed,brains were removed,and hippocampi were isolated for detection of apoptosis in hippocampal neurons (by flow cytometry) and expression of CaN,phosphor-BAD (p-BAD) and caspase-3 in hippocampal tissues (by Western blot).Apoptotic rate was calculated.Results Compared with the value at 1 day before operation,the escape latency was significantly prolonged,the frequency of crossing the original platform was decreased,the time of staying at the platform quadrant was shortcned,apoptotic rate was increased,and the expression of CaN,p-BAD and caspase-3 in hippocampal tissues was up-regulated at each time point after operation in group S (P＜0.05).Compared with group S,the escape latency was significantly shortened,the frequency of crossing the original platform was increased,the time of staying at the platform quadrant was prolonged,apoptotic rate was decreased,and the expression of CaN,p-BAD and caspase-3 in hippocampal tissues was down-regulated at each time point after operation in group N (P＜0.05).Conclusion The mechanism by which nimodipine inhibits apoptosis in hippocampal neurons and reduces postoperative cognitive dysfunction may be related to inhibition of CaN activation in aged rats.