Everolimus vs. rapamycin for treating diabetic nephropathy in diabetic mouse model

In order to evaluate the effectiveness of everolimus vs. rapamycin in the treatment of diabetic nephropathy, 8-week old diabetic (db/db) mice received everolimus (2 mg/kg every day) or rapamycin (2 mg/kg every day) for 4 weeks or 12 weeks respectively. Blood and 24-h urine samples were collected for biochemical tests. One kidney from each mouse was homogenized for protein analysis and the other was removed for histological analysis. The expression levels of transforming growth factor-β1 (TGF-β1)and phospho-p70s6k were detected by using ELISA and Western blot, respectively in the renal tissue as well as in mesengial cell culture samples. Everolimus was significantly more effective than rapamycin in improving indexes of renal function and glomerular hypertrophy, and in decreasing accumulation and expansion of the extracellular matrix. However, everolimus inhibited TGF-β1 secretion and p70s6k phosphorylation induced by high glucose in vitro less efficiently than rapamycin at the same dose. Everolimus was more effective than rapamycin in preventing diabetic nephropathy in vivo, which may be contributed to the fact that everolimus has better bioavailability and a higher oral absorption rate.