Crocin alleviates the inflammation and oxidative stress responses associated with diabetic nephropathy in rats via NLRP3 inflammasomes

Aim: Currently, drugs for the treatment of diabetic nephropathy (DN) are lacking. This study aimed to explore the protective effect of crocin on DN. Main methods: Diabetes was induced in rats by streptozotocin (STZ), and changes in metabolism and renal parameters after crocin treatment were measured. Dihydroethidium (DHE) fluorescence and superoxide generation were used to detect the levels of reactive oxygen species (ROS) in rat renal tissues. Enzyme-linked immunosorbent assay was used to measure changes inflammation-related factors with crocin treatment. In addition, the expression of Nod-like receptor family pyrin domain-containing 3 (NLRP3) signaling pathway components was detected by western blot analysis, qRT-PCR, and immunohistochemistry. Key findings: Crocin lowered blood sugar, increased serum insulin levels, and improved diabetes-related symptoms, including kidney dysfunction. Masson trichrome staining revealed that crocin could improve renal tissue fibrosis caused by hyperglycemia. Moreover, crocin inhibited ROS production in renal tissues and generally inhibited the production of the proinflammatory factors TNF-alpha, IL-18, and IL-18. Crocin exerted these functions by inhibiting the expression of the NLRP3 inflammasome in DN rats. Significance: Crocin alleviates DN related oxidative stress and inflammation by inhibiting NLRP3 inflammasomes. Our results provide a new target for the treatment of DN.