Protective effects of salidroside against isoflurane-induced cognitive impairment in rats

Postoperative cognitive dysfunction, which is associated with a wide range of cognitive functions including working memory, long-term memory, information processing, attention, and cognitive flexibility, is a major clinical issue in geriatric surgical patients. The aim of the current study was to determine the protective role and possible mechanisms of salidroside against isoflurane-induced cognitive impairment. Sprague Dawley rats were randomly assigned to five groups and were treated with or without salidroside before isoflurane exposure. Open-field and fear conditioning tests were conducted to evaluate the cognitive function of the rats. Moreover, the hippocampus tissues were obtained for biochemical analysis. The results showed that the isoflurane anesthesia decreased the freezing time to context significantly at 48 h after the isoflurane exposure in the fear conditioning test. Salidroside could ameliorate isoflurane-induced cognitive dysfunction. Further analysis demonstrated salidroside markedly suppressed the release of tumor necrosis factor-α and interleukin-1β. Moreover, salidroside reversed the decreased activity of choline acetyltransferase, superoxide dismutase, glutathione peroxidase, and content of acetylcholine, as well as the increased activity of acetylcholine esterase and content of malondialdehyde in hippocampal tissue of isoflurane-exposed rats. According to the results, we concluded that that salidroside has a protective effect against isoflurane-induced cognitive dysfunction by inhibiting excessive inflammatory responses, decreasing oxidative stress, and regulating the cholinergic system.