Effect of sleep deprivation on cognitive function in rats undergoing propofol anesthesia

Abstract

Objective To evaluate the effect of sleep deprivation on cognitive function in the rats undergoing propofol anesthesia. Methods Sixty healthy male Sprague Dawley rats, aged 14-18 weeks, weighing 200-250 g, were randomly assigned into 3 groups(n=20 each)using a random number table: control group(group C), propofol anesthesia group(group P), and sleep deprivation+ propofol anesthesia group(group SDP). Propofol was given as a bolus of 15 mg/kg followed by an infusion of 40 mg·kg-1·h-1 for 2 h in group P. After the rats were subjected to rapid eye movement sleep deprivation for 24 h, the rats received propofol anesthesia in group SDP.Before sleep deprivation, after sleep deprivation, and at 1, 3 and 7 days after anesthesia, Morris water maze test was used to assess the learning and memory function, and the escape latency and frequency of crossing the original platform were recorded.Ten rats randomly selected from each group at 1 and 7 days after anesthesia were sacrificed, and brains were removed to observe the morphology of nerve cells in the hippocampal CA1 region(by Nissl's staining)and to detect the expression of phosphorylated Tau at Thr231(Tau-pThr231)in the hippocampal CA1 region(by immunohistochemisty). Results Compared with group C, the escape latency was significantly prolonged, the frequency of crossing the original platform was decreased, the expression of Tau-pThr231in the hippocampal CA1 region was up-regulated at 1 day after anesthesia in P and SDP groups(P 0.05). The pathological changes were aggravated at 1 day after anesthesia in group SDP compared with group P, and there was no significant difference at 3 and 7 days after anesthesia between group SDP and group P. Conclusion Sleep deprivation can aggravate the transient cognitive dysfunction after propofol anesthesia, and the mechanism is related to promotion of Tau phosphorylation in the rats. Key words: Sleep deprivation; Propofol; Cognition disorders