Effects of different concentrations of sevoflurane on cognitive function in neonatal rats

Objective To evaluate the effects of different concentrations of sevoflurane on the cognitive function in neonatal rats.Methods Twenty-four neonatal Sprague-Dawley rats of both sexes,aged 7 days,weighing 12-16g,were randomly divided into high concentration sevoflurane group (group Sev1),low concentration sevoflurane group (group Sev2) or control group (group C),with 8 rats in each group.Sev1 and Sev2 groups were exposed to 2％ and 4％ sevoflurane for 6h,respectively,and C group inhaled gas mixture composed of 30％ oxygen.At 2 and 8 weeks after exposure to sevoflurane,cognitive function was assessed using the open field test and Morris water maze test.Results In the open field test,no significant differences were observed among the three groups (P ＞ 0.05).Morris water-maze test showed that the escape latency was significantly prolonged,and the frequency of crossing the original platform and the time spent in the third quadrant were decreased at 2 weeks after exposure to sevoflurane in Sev1 group and at 2 and 8 weeks after exposure to sevoflurane in Sev2 group as compared with group C (P ＜ 0.05).Morris water-maze test showed that the escape latency was significantly prolonged,and the frequency of crossing the original platform and the time spent in the third quadrant were decreased at 2 and 8 weeks after exposure to sevoflurane in Sev2 group compared with Sev1 group (P ＜ 0.05).Conclusion Exposure to 4％ and 2％ sevoflurane for 6h both can induce cognitive decline and the decreasing effect is enhanced with the increasing concentration in the neonatal rats. Key words: Anesthetics, inhalation;  Infant, newborn;  Cognition