Role of cytochrome P450 products of arachidonic acid metabolism in the renal complications of diabetes mellitus in rats -

Abstract

Background: Diabetic Nephropathy(DN) is a serious life threatening condition associated with both type I and type II diabetes. It is usually characterized by renal hypertrophy, extracellular matrix accumulation, protenuria which eventually accumulates into renal failure and kidney function loss. Early stages are also often associated with abnormal sodium load handling and consequent hypertension. Such processes are linked by the arachidonic acid(AA) metabolites 20-hydroxyeicosatetraenoic acid (20-HETE) and epoxyeicosatrienoic acids (EETs) produced by several cytochrome P450 enzyme isoforms. AA metabolism is altered in rat models of type I diabetes.Aim: The present study aims at determining the role of 20-HETE and various EETs in renal hypertrophy and extracellular matrix accumulation which contribute to the pathophysiology of diabetic nephropathy. In addition, the role of CYP450 enzymes as promising therapeutic agents in both the development and progression of diabetic nephropathy will be investigated.Methods: Male Sprague Dawley rats were adopted as animal models for this experiment. Diabetes will be induced by Streptozotocin and renal parameters will be studied at different stages of diabetes. Urine protein excretion will be assessed. Western Blot analysis will be performed to determine levels of CYP4A, Nox4 and fibronectin. Trichrome stains will be used to assess collagen deposition, PAS stains to assess the level of proteoglycan deposition and DHE stain to assess ROS generation. Levels of 20-HETE and EET in urine will be measured at day 28 of the experiment.Results: Diabetes is associated with renal enlargement, mesangial matrix deposition, collagen deposition, ROS production, fibronectin expression and an increase in the urinary excretion of 20-HETE. Treatment with either HET0016 or BNF reduces these injury indexes.Conclusion: Our results indicate that hyperglycemia in diabetes has a significant effect on the expression of AA-metabolizing CYPs, manifested by increased AA metabolism, and might thus alter kid