Experimental Study On The Expession Of ICAM-1mRNA In The Myocardium Of Neonatal Rat Model With Hypoxic-ischemia Reperfusion Brain Damage Of Bilirubin Intervention

Objective To study the protective effect of bilirubin in the hypoxic-ischemic myocardial injury through establishing the classic neonatal rat model with hypoxicischemia reperfusion(HIR) brain damage model.Bilirubin and PNS intervention in the newborn SD rats of the classic model of HIR,ICAM-1mRNA expression were determined,to verify the protective effect and mechanism of bilirubin in hypoxicischemic myocardial injury and compare the protective effect of Bilirubin and PNS. To seek a new theoretical foundation for the treatment of hypoxic-ischemic myocardial injury.Methods 72 7-day-old newborn SD rats(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 bilirubin 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 after 12 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 groupⅡ.The rats of every group were killed after establishing HIR model 6 hours,24 hours.8 animals were killed in corresponding time pionts.Their myocardium tissues were fixed,they were made into paraffin section,then,treated with in situ hybridization techniques.Use cell count evaluation of positive cell and semi-quantitative evaluation of positive intensity.At last the data were processed with SPSS11.5 statistical method.Results(1) Compared groupⅠwith groupⅡ,the expression of ICAM-1mRNA of groupⅡwas significantly higher(P＜0.01).And the expression of ICAM-1mRNA of groupⅡwas decreased in comparing groupⅡ6h with groupⅡ24h.(2) The expression of ICAM-1mRNA in groupⅢ,groupⅣwas significantly decreased,comparing with groupⅡ(P＜0.01).(3)Compared groupⅢwith groupⅣ,there was no significant difference(P＞0.05).(4) The expression of ICAM-1mRNA of groupⅤwas higher than that of groupⅡ(P＜0.05).Conclusions The mechanism of the protective effect of bilirubin in hypoxic—ischemic myocardial damage may be related to reducing inflammatory protein(such as ICAM-1) gene transcription.Compared with the effects of PNS which is well known as antioxidation,the protective effect of bilirubin is no significant difference.