Low-doses of fenofibrate and dipyridamole have pleiotropic renoprotective actions in diabetic rats. This study investigated their combined effect relative to their individual treatments and lisinopril in rats with diabetic nephropathy. Streptozotocin (55mg/kg, i.p., once)-administered diabetic rats were allowed for 10 weeks to develop nephropathy. Diabetic rats after 10 weeks developed nephropathy with discernible renal structural and functional changes as assessed in terms of increase in kidney weight to body weight ratio (KW/BW), and elevations of serum creatinine, urea and uric acid, which accompanied with elevated serum triglycerides and decreased high-density lipoproteins. Hematoxylin-eosin, periodic acid Schiff and Masson trichrome staining confirmed renal pathological changes in diabetic rats that included glomerular capsular wall distortion, mesangial cell expansion, glomerular microvascular condensation, tubular damage and degeneration and fibrosis. Low-dose fenofibrate (30mg/kg, p.o., 4 weeks) and low-dose dipyridamole (20mg/kg, p.o., 4 weeks) treatment either alone or in combination considerably reduced renal structural and functional abnormalities in diabetic rats, but without affecting the elevated glucose level. Fenofibrate, but not dipyridamole, significantly prevented the lipid alteration and importantly the uric acid elevation in diabetic rats. Lisinopril (5mg/kg, p.o., 4 weeks, reference compound), prevented the hyperglycemia, lipid alteration and development of diabetic nephropathy. Lipid alteration and uric acid elevation, besides hyperglycemia, could play key roles in the development of nephropathy. Low-doses of fenofibrate and dipyridamole treatment either alone or in combination markedly prevented the diabetes-induced nephropathy. Their combination was as effective as to their individual treatment, but not superior in preventing the development of diabetic nephropathy.
This study investigated the pretreatment and post-treatment effects of dipyridamole (20 mg/kg/day, p.o.) in gentamicin-induced acute nephrotoxicity in rats. Rats were administered gentamicin (100 mg/kg/day, i.p.) for 8 days. Gentamicin-administered rats exhibited renal structural and functional changes as assessed in terms of a significant increase in serum creatinine and urea and kidney weight to body weight ratio as compared to normal rats. Renal histopathological studies revealed a marked incidence of acute tubular necrosis in gentamicin-administered rats. These renal structural and functional abnormalities in gentamicin-administered rats were accompanied with elevated serum uric acid level, and renal inflammation as assessed in terms of decrease in interleukin-10 levels. Dipyridamole pretreatment in gentamicin-administered rats afforded a noticeable renoprotection by markedly preventing renal structural and functional abnormalities, renal inflammation and serum uric acid elevation. On the other hand, dipyridamole post-treatment did not significantly prevent uric acid elevation and renal inflammation, and resulted in comparatively less protection on renal function although it markedly reduced the incidence of tubular necrosis. In conclusion, uric acid elevation and renal inflammation could play key roles in gentamicin-nephrotoxicity. Dipyridamole pretreatment markedly prevented gentamicin-induced acute nephrotoxicity, while its post-treatment resulted in comparatively less renal functional protection.