Changes in expression of hippocampal occludin and claudin-5 after operation in aged rats

Abstract

Objective To investigate the changes in the expression of hippocampal occludin and claudin-5 after operation in aged rats. Methods Eighty-one healthy male Wistar rats, aged 16–18 months, weighing 400–500 g, were randomly assigned into 3 groups(n=27 each)using a random number table: normal control group(group C), skin incision group(group I)and splenectomy group(group S). Splenectomy was performed in group S. Only skin incision and closing were performed in group I. Morris water maze test was performed before operation and on 1, 3 and 7 days after operation.The escape latency and the percentage of time spent at the target platform quadrant were recorded.Nine rats randomly selected from each group were sacrificed after the end of the test, and the hippocampi were isolated to detect the expression of occludin and claudin-5 by Western blot. Results Compared with group C, the escape latency was significantly prolonged, the percentage of time spent at the target platform quadrant was decreased, the expression of hyperphosphorylated occludin and claudin-5 was down-regulated, and the expression of hypophosphorylated occludin was up-regulated on 1 and 3 days after operation in group S(P<0.05). Conclusion The mechanism of postoperative cognitive dysfunction is related to the down-regulated expression of hippocampal hyperphosphorylated occludin and claudin-5 in aged rats. Key words: Cognition disorders; Hippocampus; Aged; Tight junctions; Postoperative complications