Effects of postoperative sleep deprivation on expression of choline acetyltransferase in hippocampi of aged rats

Abstract

Objective To investigate the effects of postoperative sleep deprivation on the expression of choline acetyltransferase (ChAT) in hippocampi of aged rats. Methods Forty-eight male Wistar rats, aged 20 months, weighing 500-600 g, were randomly divided into 4 groups (n = 12 each) using a random number table: control group (group C); operation group (group O); sleep deprivation group (group S); postoperative sleep deprivation group (group OS). Sleep deprivation was induced in the rats by housing them on small platforms over water.They fell into the water if they lost muscle tone.All the rats had free access to food and water.In group OS, splenectomy was performed, and all the rats underwent 24 h sleep deprivation after the rats were awake.All the rats underwent 24 h sleep deprivation at the corresponding time point in group S. Morris water maze test was carried out at 24 h after operation.The number of ChAT positive cells in the hippocampal CA1 region was counted after completion of Morris water maze test. Results Compared with group C, the escape latency was significantly prolonged, the time of staying at the original platform quadrant was shortened, and the frequency of crossing the original platform and the number of ChAT positive cells in the hippocampal CA1 region were decreased after operation in O and OS groups, and no significant changes were found in the parameters mentioned above in group S. Compared with group O, the escape latency was significantly prolonged, the time of staying at the original platform quadrant was shortened, the frequency of crossing the original platform was decreased, and there was no significant difference in the numberof ChAT positive cells in the hippocampal CA1 region in group OS, and no significant changes were found in the parameters mentioned above in group S. Compared with group S, the escape latency was significantly prolonged, the time of staying at the original platform quadrant was shortened, and the frequency of crossing the original platform and the number of ChAT positive cells in the hippocampal CA1 region were decreased after operation in group OS. Conclusion The mechanism by which postoperative sleep deprivation induces cognitive decline is not related to the expression of ChAT in hippocampi of aged rats. Key words: Sleep deprivation; Choline O-Acetyltransferase; Cognition disorders