Effects of isoflurane anesthesia on NR1 expression and neuronal apoptosis in hippocampus and cortex of adult rats

Abstract

Objective To evaluate the effects of isoflurane anesthesia on NR1 expression and neuronal apoptosis in the hippocampus and cortex of adult rats .Methods Thirty-six adult male Sprague-Dawley rats , weighing 250-280 g ,were randomly assigned into 3 groups using a random number table ：control group （group C , n=6 ） ,O2 inhalation group （group O , n=6 ） and isoflurane anesthesia group （group I , n=24 ） .The rats were exposed to 2% isoflurane （group I） ,to pure oxygen （group O） ,or to air （group C） for 2 h .At 2 h ,and 1 ,7 and 14 days after the rats were awake （T1-4 ） ,Morris water maze test was performed .The rats were then sacrificed and brains were removed for isolation of the hippocampus and cortex .NR1 expression was detected using SABC immuno-histochemical technique and neuronal apoptosis was determined using TUNEL .Results Compared with group C , the escape latency at T2 and total swimming distance at T1 ,2 were significantly prolonged , and the expression of NR1 in hippocampi was down-regulated at T1 ,2 in group I ,and the expression of NR1 in the cortex was down-regulated in O and I groups （ P 0.05 ） .Conclusion Isoflurane anesthesia can decrease the cognitive function transiently ,which is related to inhibition of up-regulation of NR1 expression in the hippocampi ,but not related to neuronal apoptosis in adult rats . Key words: Isoflurane; Cognition disorders; Hippocampus; Receptors,N-methyl-D-aspartate; Apoptosis