Long-term action of propofol on cognitive function and hippocampal neuroapoptosis in neonatal rats

Propofol is a short-acting anesthetic and generally is utilized for the induction and maintenance of anesthesia in pediatrics and adults. However, whether repeated use of propofol affects long-term cognitive function remains unclear. This study investigated the effects of propofol on cognitive function and hippocampal neuroapoptosis in neonatal rat. A total of 112 male newborn 7-day old Sprague-Dawley rats were randomly divided into 8 groups (n=14 rats per group) and intraperitoneally injected either with saline or propofol at 50, 100, and 150 mg/kg/day for 5 consecutive days. Four non-surgical groups were assigned as Con1, P50, P100, and P150. Four surgical groups were received an appendicectomy under propofol anesthesia and assigned as Con2, SP50, SP100, SP150. After 2 months raising, cognitive function, hippocampal neuroapoptosis, and intracephalic inflammatory cytokines were evaluated. There was no obvious effect on the cognitive function and neuroapoptosis after repeated use of propofol at a low dose for 5 days, whereas repeated use of propofol at a middle/high dose significantly increase the expression of apoptotic factors (caspase-3 and Bax), pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α), and impair the cognitive function. Thus, our data suggest that repeated use of propofol at a low dose may be safe during the period of brain growth spurt. Using propofol at a recommended or higher dose for anaesthesia may lead to the cognitive defects, attributed to hippocampal neuroapoptosis and the overexpression of pro-inflammatory cytokines in the brain.