Abstract:

Objective To investigate the effects of rapamycin on podocytes of rats with diabetic nephropathy. Methods Diabetic SD rat models were established by intraperitoneal injection of streptozotocin (STZ). After model establishment, diabetic SD rats were randomly divided into rapamycin treatment group (rapamycin treatment for 4 weeks since the twelfth week after model establishment, n=6) and diabetic nephropathy group (intragastric administration of the same amount of normal saline for 4 weeks since the twelfth week after model establishment, n=6), and 6 SD rats without model establishment were served as normal control group. Twenty-four h urinary protein excretion was determined by BCA protein assay. The histological changes of kidney were observed by light microscopy, and the foot processes effacement and width of foot processes were determined with electron microscopy. Laser confocal microscopy with immunofluorescence staining and Western blotting were employed to detect the expression of desmin and podocin. Results Compared with diabetic nephropathy group, the 24 h urinary protein excretion in rapamycin treatment group was significantly reduced (P<0.05). The glomerular pathological changes were alleviated by rapamycin treatment. The width of foot processes was shorter in rapamycin group than in diabetic nephropathy group (P<0.05). There was lower expression of desmin and higher expression of podocin in podocytes in rapamycin treatment group. Conclusion Rapamycin may attenuate the urinary protein in rats with diabetic nephropathy, which may be associated with the protection of podocytes by rapamycin.

Key words: rapamycin, diabetic nephropathy, proteinuria, podocyte, desmin, podocin