Prevention of Diabetic Nephropathy in 12 Week STZ Induced Diabetic Rats Treated by C-peptide

Purpose To investigate the prevention effect of C peptide on diabetic nephropathy in STZ rats. Methods The study included 4 groups of rats:(1) intensive treated diabetic group (DM?I group) with nearly normal blood glucose level;(2) C peptide (130 nmol/kg,sc,twice daily)diabetic group (DM?C group) with constant high blood glucose level;(3) non treated diabetic group (DM group) with the same blood glucose level as DM?C group;(4) age matched non diabetic control rats (N group).After 12 weeks of diabetes,ratio of kidney weight/body weight(KW/BW),glomerular volume [ V (glom)],extracellular mat rix area fraction of glomerular cross section [ S (ECM)/ S (glom)],glomerular basement membrane thickness (GBMT) and urinary albumin excretion rate (UAER) were measured. Results DM?C group had V (glom) and S (ECM)/ S (glom) similar to those of DM?I group and N group,which were approximately 51% and 74% respectively of those in DM group ( P 0.001).KW/BW and UAER of DM?C group were the same level as DM group ( P 0.05) while increased compared to DM?I group ( P =0.03 and 0.05 res pectively).GBMT of all groups had no statistical difference. Conclusions The accumulation of glomerular extracellular matrix which leads to mesangial expansion and glomerular hypertrophy can be completely prevented by 12 week C peptide treatment independent of metabolic control in STZ rats.But there is no prevention effect on whole kidney hypertrophy and leakage of urinary albumin.