Profile of reactive oxygen species generation and antioxidative mechanisms in the maturing rat kidney

The antioxidative potential and reactive oxygen species generation were assessed in rat kidney during early critical periods of development and maturation. Superoxide anion generation was found to be low in kidney during early postnatal days of development, whereas hydrogen peroxide levels remained unaltered during development. The levels of thiobarbituric acid reactive substances and protein carbonyls in developing kidney were higher during early postnatal days, up to 26 days after birth, compared to the adult levels. Kidney sulphydryl contents were significantly less during early periods (9 days postnatally) of development compared to adults but attain adult value by postnatal day 26. The levels of ascorbic acid and ceruloplasmin were also higher in developing kidney than in adults. Among enzymic antioxidants, the levels of glutathione peroxidase (GPx) enzyme in developing kidney were high during the early developmental period of the study as compared to adults; however, superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR) were found to be significantly low at early postnatal days up to 16 days of age, which subsequently attained maturational level by the age of 26 days. The levels of antioxidant enzymes and sulphydryl contents in the developing kidney during early periods after birth are low but they increase subsequently with increasing age. Therefore, the present finding suggests that immature kidneys are in a highly dynamic stage of development during the early period and are equipped with antioxidative defence mechanisms that may have a predominant role in protecting against oxidative challenge.