Myocardial Matrix Metalloproteinases Activities In Mice With Myocardial Injury After Asphyxia

Objective The purpose of this study was to investigate the dynamic changes in myocardial matrix metalloproteinases( MMPs) activity in neonatal rats with asphyxia, the relationship between MMPs activity and both cardiac function and the quantity of myocardial collagen .Method Sixty seven to ten days old neonatal Wistar rats were randomly divided into four groups:Control group(n=15);Asphyxia groupsA₁, A₂ and A_{1 day, 7days, 14days after asphyxia,n1 =n2 =n3=15}. In the asphyxia groups, animal model was reproduced by normobaric asphyxia. Three groups rats with asphyxia and the control rats were sacrificed on each of days 1, 7 and 14days after asphyxia. Then tested the serum concentrations of cardiac troponin I. The myocardial MMPs-3, 9 activity was measured on immunohistochemical assay. Histological cross sections of the hearts were stained with hematoxylin-eosin and myocardial histopathological scores were determined under an optical microscope. The amount of myocardial collagen was measured by means of chloramines T.Result: In the asphyxia groups, the serum concentrations of CnTI was significantly higher than in control rats on day 1 ( P < 0.05),then lower on day 7(P < 0.05),and recovered to the normal level on day 14((P > 0.05). In asphyxia groups,MMPs-3 activities were significantly higher than in control rats , reaching a peak on day 7 ( P <0.05) and gradually decreasing later;On day 14,the activities still higher than day l(compared with the control groups, P < 0.05). The myocardial MMPs-3 activity...