Impairment of congnitivefunction in rats by propofol or isotlurane anesthesia and differential expression of c-Fosand E-GR-1

：Objective To investigatethe changes in rat cognitive function and c-Fos, EGR-1 expression in rat hippocampus CAIafter propofol or isoflurane anesthesia in rats. Methods Sixty 3-month-young rats andsixty 20-month-old rats were ramdomly divided into 4 groups respectively: the controlgroup, the Morris Water Maze (MWM) group, the propofol anesthetized group(ratsanesthetized by propofol for 2 h or 4 h, then performed MWM test to assess the cognitivefunction 2 day or 2 weeks later: P2d, P4d, P2W, P4W), and the isoflurane group (ratsinhaled 1.2% anesthetized for 2 h or 4 h0 then performed MWM test to assess the cognitivefunction 2 day or 2 weeks later: I2d, I4d, I2W, I4W). Rats were killed immediately afterthe test, and the hippocampus were isolated for determination of c-Fos and EGR-1 usingimmumo-histochemical and non-radiocative protein kinase assay technique. Results Fourhour's isoflurane anesthesia could induce cognitive decline in rats of both age(P<0.05). The impairment of spatial memory existed at least 2 weeks after anesthesia, and wasmore serious in old rats than in young rats(P< 0.05); 4 hours propofol anesthesiadecreased cognitive function only in old rats(P< 0.05), with less impairment comparedto isoflurane anesthesia (P< 0.05). The result of immu-mohistochemical showed that theexpression of c-Fos and EGR-1 in MWM group was significantly higher than that of thecontrol group (P< 0.05) ; c-Fos expression in I4d, I4W group of old rats, P4d group ofyoung rats and EGR-I expression in I4d group of old rats were decreased compared with thatin MWM group (P< 0.05). Conclusion Impairment of rat cognitive function by propofol orisoflurane lasted for 2 weeks post anesthesia, which was more serious in isoflurane groupand exhibited positive correlation with age and anesthesia duration. Inhibition of c-Fosand EGR-1 expression post anesthesia might play an important role in postoperativecog-nitive dysfunction.