The impact of dexmedetomidine on the cognitive function after splenectomy in aged rats

WANG Shanshan; YANG Xiaoming; WANG Tao

Abstract：Objective To investigate the impact of dexmedetomidine on the POCD(postoperative cognitive dysfunction) and the expression of HMGB1(high mobility group box-1)in hippocampus in aged rats.Methods 24 SD male rats aged 18~20 months were randomly divided into 3 groups(n=8): normal control group(group C), surgical group(group S), and dexmedetomidine group(group D). POCD was induced by splenectomy. After the operation, 24 rats were underwent Morris maze test. On the 1~6 days after operation, all the rats underwent place navigation test, and on the seventh day they underwent spatial probe test, to observe their learning and memorizing ability. After the Morris test, the rats were executed and their brains were obtained. The expression of HMGB1 in the CA1 region of hippocampus was detected by immunohistochemical method.Results Compared with group C, the escape latency were extended(P<0.05); the time percentage of original platform quadrant and the times of crossing the original platform decreased(P<0.05), and the expression of HMGB1 in the CA1 region of hippocampus were increased in group S(P<0.05). However, the dexmedetomidine significantly reduced the escape latency(P<0.05), increased the time percentage of original platform quadrant and the times of crossing the original platform(P<0.05), and reduced the expression of HMGB1 in the CA1 region of hippocampus as compared with group S(P<0.05).Conclusion Dexmedetomidine improved postoperative cognitive dysfunction in aged rats,and this effect may be related to its decreasing HMGB1 expression in CA1 region of hippocampus.