| Purpose:Postoperative Cognitive Dysfunction is a common complication after surgery. Thepatients usually suffer from barriers in personality, social skills and cognitive abilitiesas well as decrease in memory and attention. POCD could severely affect quality ofpeople’s life and prolong the patients’ hospitalization, as a result, increasing costs,bringing a heavy burden to the patients and their families. The pathogenesis of POCDis still not fully described, and this study focuses primarily on nerve degeneration,nerve inflammation and apoptosis. Caspase-3is the key to apoptosis molecule. NitricOxide plays an important role in learning and memory. NO is not stable, its activity isexpressed by the generation of Nitric Oxide Synthase, and the Neuronal Nitric OxideSynthase (nNOS) is one of the NOSs. Sevoflurane is commonly used inhaledanesthetics and continuous oxygen inhalation is the major measure during anesthesiato prevent hypoxia. Sevoflurane and oxygen on the influence of postoperativecognitive function has not been described. This thesis studies the impact ofinteraction between sevoflurane and different concentration of oxygen toHippocampus nNOS, caspase-3and the expression of synaptophysin and cognitivefunction of aged mice.Method:60healthy male C57/BL6elderly mice (14months) were randomly divided intofive groups: group of high concentration of oxygen (HO group, n=22): inhaling100%oxygen for4h; high concentration of oxygen+sevoflurane group (HS group,n=22): taking in100%oxygen with2.5%sevoflurane for4h; moderateconcentration of oxygen group (MO group, n=22): inhaling40%oxygen for4h;moderate concentration of oxygen+sevoflurane group (MS group, n=22):inhaling40%oxygen with2.5%sevoflurane for4h; control group (Con group, n= 22): taking in air for4h. Separately, cognitive in the elderly mice was determined inthe Morris Water Maze. Western Blot is used to test the expression of nNOS,caspase-3in hippocampus. And Immunofluorescence is applied to test theexpression of synaptophysin.of the mice hippocampal CA1.Result:A comparison between group Con and other groups is made and the results are asfollows: MO group crossed the platform in more times（P=0.0028）, its nNOSexpression in hippocampal zone significantly increased（P=0.0396） and the sameincrease is found in synaptophysin expression in hippocampal CA1zone（P=0.0067）, but not in caspase-3expression of hippocampal zone. HO group’snNOS expression increased greatly（P=0.0317）, but not in times of crossing theplatform, caspase-3and synaptophysin expression in hippocampal zone. MS grouphas no difference in times of crossing the platform, nNOS expression, caspase-3expression and synaptophysin expression in hippocampal zone. But, compared withgroup Con, HS group passed through the platform in much less times（P=0.0227）,while their caspase-3expression increased significantly（P=0.0359）and theirsynaptophysin expression in hippocampal CA1zone decreased(P=0.0007).Compared with HO group, MO group had a significant increase in the number ofcrossing platform(P=0.0002), and synaptophysin in mice hippocampal CA1areaalso increased(P=0.0434); Compared with the MS group, MO group crossed theplatform in much more times (P=0.0002), and synaptophysin in hippocampal CA1region also significantly increased (P=0.0009);Compared with the HO group, HSgroup has a significant reduction in the number of crossing platform(P=0.0134),caspase-3expression in the hippocampus significantly increased (P=0.0199), andsynaptophysin in hippocampal CA1region significantly decreased (P=0.0075).Compared with the MS group, HS group had a significant reduction in the number of crossing platform (P=0.0019), caspase-3expression levels in the hippocampussignificantly increased (P=0.0132), and synaptophysin in hippocampal CA1regionsignificantly reduced (P=0.0075).Conclusion:1. Inhaling40%oxygen can improve the cognitive function of the elderly mice, andinhaling100%oxygen has no impact on cognitive function in the elderly mice;2. Inhaling2.5%Sevoflurane with100%oxygen can cause congntive dysfunctionof the aged mice;3. Inhaling2.5%Sevoflurane with40%oxygen has no impact on cognitive functionin the elderly mice;4. Inhaling2.5%Sevoflurane with100%oxygen can increase expression ofcaspase-3, induce apoptosis, and reduce expression of synaptophysin. |
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