Effects of Repeated Inhalation of Sevoflurane During Infancy on Cognitive Function and Hippocampal Volume of SD Rats in Childhood and Adulthood

Abstract

Background: It has been reported that repeated exposure to sevoflurane, a widely used general anesthesia in pediatric surgeries, may lead to brain defect in infant. However, the long-term effect of repeated exposure to sevoflurane during infancy on the learning behavior and neuro-development is less investigated yet.Methods: Sixty-four SD (sprague dawley) rats were randomly divided in to two groups, the experimental group (n=32) was exposed to sevoflurane (2.6%, 2 h) and the control group (n=32) was exposed to carrier gas (1 L/min O2 + 1 L/min Air, 2 h) for three times at infancy (P (postnatal day) 7, P14, and P21). At childhood (P32 to P36), SD rats in each group (n=16) received Morris Water Maze (MWM) test, and then Magnetic Resonance Imaging (MRI) was used to scan their brain and hippocampus at P37. Subsequently, the same NWM test and MRI scanning was conducted for the remaining SD rats in their adulthood (P92 to P97) (n = 16/group).Results: After being exposed to sevoflurane in infancy, the hippocampal volume of SD rats significantly decreased in their childhood and adulthood, their whole brain volume was also shrunken in adulthood; however, MWM test showed there is no obvious change in their spatial learning and memory recall performance either in childhood or in adulthood.Conclusions: Although repeated exposure to sevoflurane in infancy did not affect the spatial learning and memory performance of rats, however, it could result in the decease of hippocampal and brain volume in their adulthood. This study suggests that repetitive sevoflurane exposure in infancy may exert long-term risk in brain development.