Danshen injection ameliorates STZ-induced diabetic nephropathy in association with suppression of oxidative stress, pro-inflammatory factors and fibrosis.

Diabetic nephropathy (DN) is one of the most frequent complications in diabetes mellitus. This study aimed to explore whether Danshen injection is protective to renal tissue in diabetes. Intraperitoneal injection of streptozotocin (STZ) (60mg/kg) was used to induce diabetes in rats. Some STZ-induced diabetic rats were also intraperitoneally injected with Danshen solution at two different dosages (0.5 or 1ml/kg/day) for 6weeks. Our results showed that serum creatinine (sCr) and blood urea nitrogen were significantly increased in STZ-induced diabetic rats, which was alleviated upon Danshen injection. Danshen injection was also found to ameliorate hypertrophy and dilatation of renal tubule and glomeruli possibly by decreasing the expression of collagen and fibronectin in association with suppression of TGF-β1/Smad pathway. Further investigation revealed that Danshen injection could increase the activity of superoxide dismutase (SOD), and reduce reactive oxygen species (ROS) and malondialdehyde (MDA) levels in STZ-induced diabetic rats, indicating suppression of oxidative stress. In addition, we also found that Danshen injection could suppress IκB/NF-κB signaling pathway and reduce the level of a number of pro-inflammatory factors, including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6) in the diabetic renal tissue, indicating suppression of inflammation. In conclusion, our results demonstrated that Danshen injection may rescue STZ-induced diabetic nephropathy, possibly via suppressing the oxidative stress, inflammatory responses and fibrosis progression.