Relationship between hippocampal monocyte chemotactic protein-1 and its receptor and postoperative cognitive dysfunction in aged rats

Abstract

Objective To evaluate the relationship between hippocampal monocyte chemotactic protein-1(MCP-1)and its receptor C-C chemokine receptor 2(CCR2)and postoperative cognitive dysfunction(POCD)in aged rats. Methods Forty-eight male Sprague-Dawley rats, aged 20-22 months, weighing 480-550 g, were randomly divided into 2 groups(n=24 each)using a random number table: control group(group C)and POCD group.POCD group inhaled 2.0% isoflurane and underwent splenectomy.Before surgery and at 1, 3 and 7 days after surgery, Morris water maze test was performed to evaluate the spatial learning and memory ability.The escape latency and swimming distance were recorded.Eight rats were sacrificed after the end of Morris water maze test performed at 1, 3 and 7 days after surgery.Then the brains were removed, and the hippocampi were isolated for detection of the expression of MCP-1 and CCR2 by Western blot. Results Compared with group C, the escape latency and swimming distance were significantly prolonged, and the expression of MCP-1 and CCR2 in hippocampi was up-regulated at 1, 3 and 7 days after surgery in POCD group. Conclusion Up-regulation of hippocampal MCP-1 and CCR2 expression may be involved in the mechanism of POCD in aged rats. Key words: Chemokine CCL2; Receptors, CCR2; Hippocampus; Aged; Cognition disorders; Postoperative complications