Effects of neonatal repeated inha lation of sevoflurane on ability of learning and memory and hippocampal volume in infantile rats / 医学研究生学报

ABSTRACT

Obj cetive A large number of recent studies show that sevoflurane anesthesia may cause learning and memory dysfunction.The aim of this study was to explore changes of learning and memory ability and hippocampal volume in infantile rats after neonatal interrupted and repeated inhalation of 2.6% sevoflurane through detecting the learning and memory ability by Morris water maze and the hippocampus volume by MRI.Method s Thirty two neonatal SD rats were randomly devided into two groups (n=16):experimental group and control group.Rats inhalated 2.6%sevoflurane in the experimental group and 1 L/min O2 +1 L/min Air in the control group at the postnatal days of 7, 14 and 21 (P7, P14, P21). The learning and memory ability was determined by the Morris water maze test from P31 to P37;The brains of rats were scanned by mag-netic resonance imaging ( MRI) machine under anesthesia with 1%sodium pentobarbital at P37, and the brain and bilateral hippocampal volumes were measured. Results ①In the place navigation test, the escape latency had no significant difference between the two groups (P>0.05).In the spatial probe test, the dwelling time, movement distance and number of entering times in platform quadrant decreased slightly in experimental group compared with those in the control group, while there was no significant difference (P>0.05).②The brain volume [(1.53 ±0.18) cm3 vs (1.60 ±0.13) cm3] and right hippocampal volume [(16.15 ±1.76)mm3 vs(16.46 ±1.71)mm3] had no significant difference between the two groups (P>0.05).The left hippocampal volume [(16.46 ±1.71)mm3] was decreased in the experimental group compared with the control group [(18.10 ±2.53)mm3](P<0.05). Conclusion The learning and memory ability has no significant changes in in-fantile rats after neonatal interrupted and repeated sevoflurane inhalation and MRI examination of hippocampal volume is not sufficient for the diagnosis of cognitive dysfunction.