Salidroside from Rhodiola rosea L. attenuates diabetic nephropathy in STZ induced diabetic rats via anti-oxidative stress, anti-inflammation, and inhibiting TGF-β1/Smad pathway

Salidroside from Rhodiola rosea L. has hypoglycemic effects, and has anti-osteoporosis effect in diabetic rats. Whether it has beneficial effects on diabetic nephropathy (DN) has not been fully reported. Here, a DN rat model was established by streptozotocin (STZ). Salidroside (10, and 20 mg kg−1 d−1) were orally giving for eight weeks. The purity of salidroside was 99%. The results showed that eight weeks salidroside supplementation dose-dependently decreased blood glucose, serum insulin, serum creatinine, blood urea nitrogen (BUN), as well as urinary albumin of DN rats, repaired the pathological changes of kidney tissue, the renal sclerosis and fibrosis in the kidney of DN rats were improved, and the activities of oxidative defense system associated enzyme such as superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX) were also improved. Serum inflammatory cytokines (including tumor necrosis factor-α, monocyte chemoattractant protein-1, interleukin-1β, and interleukin-6) were decreased significantly in DN rats after eight weeks salidroside supplementation. Immunohistochemical results showed that fibrosis related proteins such as transforming growth factor-β1 (TGF-β1), phospho-Smad2 (p-Smad2), and phospho-Smad3 (p-Smad3) expression levels were decreased significantly in the kidney of salidroside treated group. Our results indicate that daily salidroside consumption could alleviate DN in rats, the main mechanisms are anti-inflammatory, anti-oxidative stress, and inhibition of the TGF-β1/Smad2/3 pathway. This study suggested that salidroside could be used as a nutrient against DN, as well as diabetes.