<i>Schisandra Chinensis</i> Polysaccharide Ameliorates Renal Dysfunction by Inhibiting Inflammatory Reactions and Oxidative Stress in Diabetic Rats

<i>Schisandra chinensis</i> (<i>S. chinensis</i>) polysaccharide (SCP) is an active ingredient from <i>S. chinensis</i> used mainly for the treatment of diabetes, owing to its antioxidant, hypoglycemic, and lipidemic-modulating activities. A rat type II diabetes mellitus model was established by giving rats a high-fat diet and streptozotocin (STZ) to investigate the protective effect of SCP against renal injury in diabetic rats. It was found in this study that fasting blood glucose, serum lipids, serum creatinine, and blood urea nitrogen levels were decreased, the insulin sensitivity was increased, and pathological injuries of the kidney were alleviated in SCP-treated groups, indicating that SCP should have a protective effect against renal injury in diabetic rats. SCP treatment reduced serum C-reactive protein and inhibited the expression of nuclear factors-κB and related inflammatory factors in the renal tissue of diabetic rats. SCP treatment also regulated the expression of Nuclear factor (erythroid-derived 2) like-2, heme oxygenase-1, and kelch-like ECH-associated protein-1, reduced serum malondialdehyde content, and increased superoxide dismutase activity. Furthermore, SCP down-regulated the expression of fibronectin, α-SMA, transforming growth factor β1, and p-Smad3, up-regulated Smad7 expression, and mitigated the collagen fiber deposition in the renal interstitium in diabetic rats. It can be concluded that the mechanism of SCP in alleviating renal injury may be related to inhibiting inflammation, increasing antioxidant stress capacity, and improving renal fibrosis in diabetic rats.