The quantitative analysis of inducible notric oxide synthase in kidney cortex of early diabetic rats

Objective To observe the changes of inducible nitric oxide synthase(iNOS) expression in the renal cortex in early stage of diabetes in rats.Methods 60 adult SD rats were randomly divided into 2 groups: normal control group and diabetes mellitus group.After induction of diabetes by injection of streptozotocin(STZ),the rat kidneys were taken: the left ones were examined by immunohistochemitry and analyzed by morphological method.The right ones were used for biochemical analysis.Results The concentration of NO and the activity of NOS were decreased in the early stage diabetes and were increased thereafter.iNOS showed an increase at first and then decreased.Immunohistochemitry showed the iNOS expression in renal glomeruli,proximal and distal tubules in DM rats,and the iNOS intensity was high at the beginning and descended quickly in the 4th week.Graphic analysis showed that the levels of iNOS reached the lowest in the 2nd week.Conclusion In early stage of type I diabetes in rats,iNOS leads to a high level NO expression causing renal damage,especially in the renal gloneruli.