The dynamic study of total antioxidative capacity and malondialdehyde in the liver of newborn rats induced by hyperoxia / 中国小儿急救医学

ABSTRACT

Objective To determine the levels of total antioxidative capacity(TAOC) and malondialdehyde(MDA) in liver exposed to hyperoxia,and to explore whether oxygen inhalation could cause liver injury in newborn rats.Methods Sixty-four newborn rats which were less than 12-hour-old were enrolled in this study.The rats were randomly divided into hyperoxia group(FiO2=0.85,n=32) and control group(air,n=32).Eight rats in each group were randomly sacrificed to obtain liver tissues at 1d,3d,7d and 14d.The TAOC of liver homogenates was detected by chemical colorimetry,and the MDA level of liver homogenates was measured by thiobarbituric acid test.Results In the hyperoxia group,TAOC in liver increased on the 1st day[(3.60±0.28)U/mg prot vs(3.39±0.19)U/mg prot,P<0.05];TAOC began to decreased on the 3rd day,and significantly lower than that of control group on the 14th day [(3.10±0.15)U/mg prot vs (3.56±0.14)U/mg prot,P<0.01].In the hyperoxia group,the MDA level increased on the 3rd day[(3.58±0.11)nmol/mg prot vs(2.82±0.14)nmol/mg prot,P<0.01],and reached a peak on the 7th day[(3.58 ±0.11)nmol/mg prot vs(2.82±0.14)nmol/mg prot,P<0.01],then decreased but still remained higher than control group on the 14th day [(2.92±0.18)nmol/mg prot vs(2.77 ±0.09)nmol/mg prot,P<0.01].Conclusion Too more MDA in liver and TAOC decrease may cause liver injury in newborn rats exposed to hyperoxia.With the oxygen inhalation time prolonging,the liver injury aggravation.