| PrefaceDuring anesthesia and operation, the respiratory and circulatory disorders often cause patients'serious hypoxia. The brain cellular re-sistant to hypoxia is very poor. The hypoxia often leads to unreversible injury. Therefore, acute hypoxia plays an important role in the preop-erational death and central nervous system damage. Preoxygenation is a routine treatment during hypoxia, but its effects and mechanisms re-main uncertain. In this study, we examined the expression of Nuclear FactorκB, induce Nitric Oxide Synthase and Manganese-Superoxide Dismutase at protein level in the brain of rat by Western blotting, im-munohistochemistry and xanthine oxidase. The expression of NF-κB, iNOS and Mn-SOD have also been associated with cellular injury and subsequent death in adult rats experiencing H/R. Therefore, it is im-portant to evaluate the effect of the preoxygenation on hypoxia/reoxy-genation.Material112 Wistar rats (230 -280g) were supplied from the Department of Laboratory Animals, China Medical University. The rats were di-vided into sixteen groups. 1 group was normal controls; 2 - 7 groups were exposed to preoxygenation (50% and 100% 02) for 15, 30, 60 minutes individually; 8-10 groups were exposed to preoxygenation (21% , 50% and 100% 02) for 30 minutes then were exposed to hy-poxia (5% 02) for 30 minutes; 11-16 groups were exposed to reox-ygenation ( 100% 02 ) for 1 hour or 6 hours after were exposed to preoxygenation (21% , 50% and 100% 02) for 30 minutes and hy-poxia (5% 02) for 30 minutes.Methods1. Western Blotting; For Western-blotting analysis, samples were resolved by SDS/PAGE (7.5% gel) and electroblotted to nitro-cellulose. The blots were incubated with NF-KB antibody. Immune complexes were visulized with alkaline phosphatase-conjugated goat anti-rabbit IgG.2. Immunohistochemistry: We used an affinity-purified iNOS an-tibodies and peroxidase marked streptavidin to detect the presence of iNOS positive cells in the brain.3. Xanthine oxidase; We mensurated Mn-SOD activity according to explains of production.4. Histology: The brain samples were fixed and embeded as re-ported method. 4μm -sections were cut and stained with a hematoxy-lin-eosin for histologic examination.5. Statistics; Data was expressed as mean D. Statistics analy-sis was performed with One-Way analysis of variation ( ANOVA) and Dunnett t test. A P <0. 05 was considered significant.Results1. The results of preoxygenationThe expression of NF-κB decreased in all preoxygenation groups.The numbers of iNOS positive cells in 50% preoxygenation for 15 mi-nutes, 30 minutes and 100% preoxygenation for 15 minutes groups were more than normal controls. The activities of Mn-SOD all in-creased in preoxygenation and that significandy increased as compared with normal controls in 100% preoxygenauon for 60 minutes.2. The results of preoxygenation-hypoxia-reoxygenation (PHR) The expression of NF-κB decreased in all hypoxia groups, whichwas the least in 100% PH group. The expression of NF-κB increased in all HR groups and peaked at 1 hour after reoxygenation. The ex-pression of NF-κB increased much more in 100% PHR group than in HR group, which still increased after reoxygenation for 6 hours. But the expression of NF-κB decreased much more in 50% PHR group than in HR group.The numbers of iNOS positive cells all increased. The number of iNOS positive cells did not significantly increased in PH group as com-pared with in hypoxia group, but that all significantly increased and peaked after reoxygenation for 6 hours. The number of iNOS positive cells all significantly increased after reoxygenation for 1 hour, for 6 hours in 100% PHR, but did not all significantly increased in 50% PHR.The activity of Mn-SOD all increased. The activity of Mn-SOD increased in PH group as compared with in hypoxia. That much more increased in HR group than in hypoxia group and the most in after hy-poxia 30 minutes and reoxygenation for 6 hours. The activity of Mn-SOD inc... |
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