| Postoperative cognitive dysfunction is one of the complications of surgical anesthesia.The main clinical manifestations are changes in cognitive function,such as decreased learning and memory,attention can not be concentrated,etc.In severe cases there will be personality changes and decreased social skills.With the aging of the population and the rapid development of medical technology,the opportunities for elderly patients to get surgical treatment continue to increase,while the incidence of POCD is also increasing year by year,seriously affecting the quality of life of elderly patients after surgery.This study was designed to explore the effects of inhaled sevoflurane at the same concentration and different duration of time on the cognitive dysfunction and the expression of NMDAR2 B and GABAR1 in different brain regions in aged rats.Fifty male SD rats were randomly divided into control group(group C,n = 10)and experimental group(group T,n = 40).The rats in each group were treated with the water maze experiment for five days to make them develop stable memory.Control groups received air at room tempreture.The experimental group inhaled sevoflurane at a 3% concentration duration was divided into T1(inhalation 2h)group,T2(inhalation 4h)group.Each group was equally divided into two groups and Morris water maze test would be done at 1 day and 7 days after sevoflurane inhalation.Then the frontal lobe and hippocampus were gathered and the m RNA transcription and protein expression of GABAR1 and NMDAR2 B were detected by RT-PCR and Immunofluorescence technique.By analyzing the results of the Morris water maze test,we found that the escape latency of hippocampus and frontal lobe in each experimental group one day after sevoflurane inhaltion significantly increased compared with the control group(P<0.05),and the number of space traversal decreased compared with the control group(P<0.05),and with the prolongation of drug effect,the greater the change,the more obvious the decline of learning and memory ability of rats.While,at 7days after sevoflurane inhalation,the escape latency of T2 group was longer than that of the control group(P<0.05),and the number of passing platform was decreased(P<0.05).There is no significant difference between control group and the group T1(P>0.05).The results of immunofluorescence showed that the expression of GABAR1 in hippocampus and frontal lobes of T1,T2 group was significantly increased compared with that of control group(P<0.05),while the expression of NMDAR2 B was significantly decreased(P<0.05),The change of hippocampus in T2 group was more obvious than that in T1,and the change of frontal lobe was not obvious in T1 group.After inhaled sevoflurane for 7 days,the expression of NMDAR2 B in the frontal lobe of T1 group was significantly decreased compared with that in the control group(P<0.05).The expression of GABAR1 and NMDAR2 B in T2 group were significantly changed compared with the control group and T1 group(P<0.05).The expression of GABAR1 and NMDAR2 B in the hippocampus was not significantly different between control group and the other test groups(T1,T2)(P>0.05).RT-PCR showed that the level of transcription of GABAR1 in hippocampus and frontal lope of the rats in groups(T1,T2)increased compared with the rats in control group at one day after sevoflurane inhalation(P<0.05),and the level of transcription of NMDAR2 B were significantly decreased(P<0.05),and T2 group slightly larger changes than T1 group.After inhalation of sevoflurane for 7 days,there is no significant difference between control group and the other test groups(T1,T2)(P>0.05).From this we conclude that anesthetics can cause spatial memory impairment in older rats,and long-term inhaled sevoflurane is more damaging than short-term inhaled anesthesia,and this damage repair takes some time.Inhalation of anesthetic sevoflurane can affect the decline of spatial memory in aged rats as well as up-regulation of GABAR1 expression and down-regulation of NMDAR2 B expression in hippocampus and frontal cortex,and then we suggest that postoperative cognitive dysfunction caused by anesthetics may be multi-lobulated and multiple brain regions to participate in the completion. |
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