Sporidiobolus pararoseus wall-broken powder ameliorates oxidative stress in diabetic nephropathy in type-2 diabetic mice by activating the Nrf2/ARE pathway

In type 2 diabetes mellitus (T2DM), hyperglycemia promotes oxidative stress and eventually leads to diabetic nephropathy (DN). Sporidiobolus pararoseus is reported to exhibit enhanced anti-oxidation properties. However, its role in DN remains obscure. This study aimed to determine the antioxidative effects of a Sporidiobolus pararoseus wall-broken powder (SPP) supplement on DN and investigate the possible underlying mechanisms. A model of T2DM was successfully established, and C57BL/6J male mice were fed a high-fat diet for 4 weeks and then injected with streptozotocin (100 mg per kg per day) for three consecutive days. After eight weeks of intervention, SPP strongly lowered fasting glucose levels, serum creatinine, serum urea nitrogen, urinary albumin and reduced glomerular hypertrophy and mesangial matrix expansion. In addition, SPP increased the activities of SOD, T-AOC, CAT, and GST and decreased the amount of MDA. Furthermore, it was revealed that SPP significantly abrogated oxidative stress not only by activating the Nrf2 gene but also by activating two Nrf2-targeted antioxidative genes (NQO-1 and HO-1) compared with metformin hydrochloride, which is widely accepted as a diabetes drug. Our study showed that SPP has antioxidant properties and delays the progression of DN; the underlying mechanism may be associated with activation of the Nrf2/ARE pathway.