Effect of ropivacaine-induced toxicity on learning and memory abilities and synaptophysin expression in immature mice

Objective To study the effect of ropivacaine-induced toxicity on learning and memory abilities and synaptophysin expression of the hippocampus in immature mice. Methods Sixty 21-d-old SD mice were randomly divided into ropivacaine inducement group (R,n=30) and sodium chloride treatment group (N,n=30).Mice in each group were subdivided into 4 subgroups according to the different injection times (24 h,and 3,7 and 60 d after convulsion or injection,n=5); the protein expression of synaptophysin in the hippocampus at each time point were detected by Western blotting.The left 10 mice in each group were performed Mirror water maze test to explore the latency in finding the platform. Results The latency in finding the platform in mice of group R was gradually shortened as time being prolonged,and significant difference was noted between each 2 time points (P＜0.05); while no significant difference was noted between each 2 time points in mice of group N (P＞0.05).The latency in finding the platform in mice of group R was obviously longer as compared with that in group N at 24 h and 3 d time point (P＜0.05),but there were no significant differences at other time points (P＞0.05).The synaptophysin expression in the hippocampus of mice in group R was significantly lower as compared with that in group N at 24 h time point (P＜0.05). Conclusion The effect of single ropivacaine toxicity on learning and memory impairment of immature mice is transitional,which might be correlated to the synaptophysin expression in the hippocampus. Key words: Ropivacaine;  Convulsion;  Learning and memory ability;  Synaptophysin