Effects Of Xinmailong On The Expression Of HSP70 And NF-κB In Myocardium Of Neonatal Rats With Asphyxia

Objective:1.To observe the changes of the myocardial heat shock protein 70(HSP70) and nuclear factor-kappa B(NF-κB) in immature myocardial hypoxia ischemia injury by establishing the model of neonatal rats with normobaric asphyxia.2.To investigate the effect of Xinmailong on the anti-immature myocardial hypoxia ischemia injury and its mechanism through observing the changes of the myocardial HSP70 and NF-κB.3.To discuss the best clinical time of administration by comparing the curative effect of Xinmailong in different time.Methods:1.Experimental grouping: Totally 128 Sprague-Dawley(SD) rats(seven day-old, 10～15g) were randomly divided into 4 groups:normal group(n=32), asphyxia group(n=32), Xinmailong preprocessing group(n=32) and Xinmailong post-processing group(n=32). Then each groups randomly divided into four time points of 3 hours,6 hours,12 hours and 24 hours, there were 8 rats at each time point.2.Model building:The model group SD rats were put into separably 55ml container with CaO-NaOH 5g,(Dthe mouth of bottles were sealed up for half an hour.then being given oxygen 120 minutes and coming back with mother rats.②Normal group:only to simulate the process of the model of neonatal rats with normobaric asphyxia, do not plug stopper and reoxygenation;③Xinmailong preprocessing group:the effects of intraperitoneal(i.p.) injection of XML(5mg·kg-1) administered five minutes before carring on the model of neonatal rats with normobaric asphyxia were studied;④Xinmailong post-processing group:the effects of intraperitoneal(i.p.) injection of XML(5mg·kg-1) administered just after carring on the model of neonatal rats with normobaric asphyxia were studied.3.To observe the pathomorphism of myocardial tissue and the level of blood CK-MB; The myocardial HSP70 and NF-κB activity was measured by immunohistochemical method.4.Statistical methods:All the data were expressed as mean±standard error (x±s), and statistical significance was evaluated by One-Way ANOVA. P<0.05 represents significance, P<0.01 represents extreme significance.Results:1.The myocardial fine structural of neonatal rats:Compared with normal group, myocardial edema and infiltration of inflammatory cells can be seen in asphyxia group at 6 hours, and with the time passed, myocardial injury is more obvious. Compared with asphyxia group at same time point, myocardial edema and infiltration of inflammatory cells can be reduced in Xinmailong preprocessing and post-processing group, and it is redued most obviously in Xinmailong post-processing group.2.Myocardial enzyme CK-MB of neonatal rats:Compared with normal group, the level of CK-MB activity rase significantly at different time points in asphyxia group, Xinmailong preprocessing and post-processing group(P<0.01), it increased in 3 hours, and continued to go up in 6,12,24 hours.Compared with that of asphyxia group, it decreased significantly at each time point in Xinmailong preprocessing and post-processing group(P<0.01). but it decreased significantly at each time point in Xinmailong post-processing group than that in Xinmailong preprocessing group (P<0.01).3.Myocardial expression of HSP70 of neonatal rats:Compared with control group, the myocardial expression of HSP70 activity rase significantly at different time points in asphyxia group, Xinmailong preprocessing and post-processing group(P<0.01), it increased in 3 hours, reached the peak in 24 hours.Compared with that of asphyxia group, it increased significantly at each time point in Xinmailong preprocessing and post-processing group(P<0.01), but it increased significantly at each time point in Xinmailong post-processing group than that in Xinmailong preprocessing group (P<0.01).4. Myocardial expression of NF-κB p65 of neonatal rats:Compared with control group, the myocardial expression of NF-κB p65 activity rase significantly at different time points in asphyxia group, Xinmailong preprocessing and post-processing group(P<0.01), it increased in 3 hours, reached the peak in 6 hours.Compared with that of asphyxia group, it decreased significantly at each time point in Xinmailong preprocessing and post-processing group(P<0.01). but it decreased significantly at each time point in Xinmailong post-processing group than that in Xinmailong preprocessing group (P<0.01).Conclusions:1.Myocardial edema and infiltration of inflammatory cells can be seen in neonatal asphyxia myocardium.Also the expression of HSP70 and NF-κB increased, which suggests that they play an important part in the pathogenesis of asphyxia.2.Xinmailong can lessen myocardial enzyme, decrease the pathological changes of myocardial injury, it protect the myocardial tissues by stimulating the expression of HSP70 and reducing the expression of NF-κB.3.Compared experimental result of Xinmailong preprocessing with that of post-processing group, myocardial hypoxia ischemia injury can improve better in latter group, which suggests that Xinmailong post-processing may protect better in myocardial hypoxia ischemia injury.