Experimental Study On The Change Of Superoxide Dismutase And Malonaldehyde In The Hypoxic-ischemic Encephalopathy Of Bilirubin Intervention Newborn Rats

Objective To study the protective effect of bilirubin in the hypoxic—ischemic myocardial injury through establishing the classic HIR model as the degree of asphyxia.Intraperitoneal injections of the newborn SD rats which were established the classic model of HIR with bilirubin and PNS,SOD activity and MDA content were determined.Comparing the protective effect of Bilirubin and PNS,in order to verify bilirnbin on superoxide dismutase activity and malonaldehyde content in myocardial tissues of newborn rats after hypoxia and ischemia,to seek a new theoretical foundation for the treatment of hypoxic—ischemic myocardial injury.Methods 7-day-old newborn SD rats 72(Kunming Medical College Animal Center) were randomly divided into 5 groups.GroupⅠ:Normal control group,groupⅡ:HIR model + Nature saline group,groupⅢ:HIR model + bilirubin intervention group,groupⅣ:HIR model + PNS intervention group,groupⅤ:HIR model + saline + Znpp group.GroupⅠ,without any deal,only to do the incision in the middle of the neck,free the common carotid artery.GroupⅡ,the newborn rats were given normal saline by intraperitoneal injection as soon as the HIR model were established.GroupⅢ,the newborn rats were given 10mg/kg bilirnbin by intraperitoneal injection as soon as the HIR model were established.GroupⅣ,the newborn rats were given 100mg/kg PNS by intraperitoneal injection as soon as the HIR model were established,the same dose of PNS was repeated by intraperitoneal injection after12 hours.GroupⅤ,the newborn rats were given the same volume of normal saline by intraperitoneal injection,24-hour before establishing HIR model,the rats of groupⅤmade by the way of peritoneal injection of Znpp 25mg/kg,the other dealing was the same as group Ⅱ.The rats of every group were killed after establishing HIR model 6 hours,24-hour.8 animals were killed in corresponding time pionts.Their myocardium tissues were fixed,the activity of SOD was determinated by xanthine oxidase,the content of MDA was determinated with thiobarbituric.At last the data were processed with SPSS11.0 statistical method and myocardium were observated with with light and electron microscopic.Results(1) The activity of SOD were significantly increased(P＜0.01),and the content of MDA were decreased significantly(P＜0.01)in groupⅠcompared with groupⅡ.(2) The activity of SOD in groupⅢ,groupⅣwere significantly increased,comparing with groupⅡ(P＜0.01);the content of MDA in groupⅢ,groupⅣwere significantly decreased,comparing with groupⅡ(P＜0.01).(3) The activity of SOD and the content of MDA in comparing groupⅢwith groupⅣwere no significant difference(P＞0.05).(4) The activity of SOD were decreased(P＜0.05),the content of MDA were increased(P＜0.05) in comparing groupⅢ6h with groupⅢ24h.(5) The activity of SOD in groupⅡwere higher than groupⅤ(P＜0.05), the content of MDA were less than groupⅤ(P＜0.05).Conclusions The mechanism of the protective effect of bilirubin in hypoxic-ischemic myocardial damage may be related to that it can reduce oxygen free radical,and enhance the capacity of cleaning oxygen free radical.