Effect Of Physostigmine Combined With Isoflurane Anesthesia On Cognitive Function In Rats

Objective To evaluate the effect of physostigmine on isflurane induced cognition deficit and inflammatory response, caspase-3 expression in hippocampus in rats.Methods eighty 18-month-old male Sprague-Dawley rats, weighing 400-450g, were randomly assigned into 4 groups (n=20 each):Control groups (groups C), isoflurane groups (group I), physostigmine+isoflurane group (group PI), and physostigmine (group P). Group C inhaled a gas mixture of oxygen and air for 6 h and group I inhaled 1.4%isoflurane for 6 h; Physostigmine 100 ug/kg was injected intraperitoneally every 8 h, totally 3 times in the group PI and group P; After the first injection,1.4% isoflurane was inhaled to the rats of group PI and same concentration of oxygen and air was inhaled to the rats of group P for 6h. Blood samples were taken immediately after the end of anesthesia for blood gas analysis. Hippocampi were isolated 12h after the end anesthesia for determination of TNF-α、IL-1β、 and IL-6 contents by ELISA and caspase-3mRNA expression by RT-PCR. The pyramid cells of hippocampi were observed for the pathological change. The cognitive function was assessed during the 2nd to 7th day after the end of anesthesia.Results There were no significant differences in the parameters of arterial blood gas analysis and blood glucose level among the 4 groups(P>0.05). Compared with group C and group P, the contents of IL-1β、and IL-6 in group I and PI were increased, the expression of caspase-3 was up-regulated, and the escape latency at 4-6d was prolonged, the probe time was shortened in group I and group PI (p<0.05), the number of apoptosis cells were increased. Compared with group I, the contents of IL-1β、IL-6 in group PI were decreased, the expression of caspase-3 was down-regulated, and the escape latency was shortened, the probe time was prolonged in group PI(P<0.05), the number of apoptosis cells were reduced than group I. There were no significant difference of the content TNF-α between four groups.Conclusion Physostigmine can improve isoflurane induced cognitive function in adult rats, which may be related to inhibition of inflammatory response and neuron apoptosis of the hippocampus.