Withaferin A-Loaded CS/β-GP Thermosensitive Hydrogel Attenuates Diabetes-Associated Renal Injury in a Diabetic Rat Model.

Diabetic nephropathy (DN) is a major complication of diabetes characterized by progressive renal dysfunction driven by oxidative stress and chronic inflammation. Although Withaferin A (WA) possesses antioxidant and anti-inflammatory properties, its clinical application is limited by poor aqueous solubility and rapid systemic clearance. This study developed a thermosensitive chitosan/β-glycerophosphate (CS/β-GP) hydrogel as a sustained-release platform for WA delivery and evaluated its renoprotective potential using high glucose-treated renal cells. An early streptozotocin-induced diabetes-associated renal injury animal model following 4 days of treatment and a 28-day observation period. The CS/β-GP-WA hydrogel demonstrated favorable physicochemical properties, including efficient drug encapsulation, thermoresponsive gelation, injectability, sustained drug release, and good batch-to-batch reproducibility. Under high-glucose conditions, the hydrogel improved cell viability, reduced intracellular reactive oxygen species generation, preserved mitochondrial membrane potential, restored antioxidant enzyme activity, and decreased pro-inflammatory cytokine production. In diabetic rats, CS/β-GP-WA treatment was associated with improved glycemic control and renal function, reflected by reduced serum creatinine, blood urea nitrogen, urinary protein, and oxidative stress markers. Histological analyses further showed preservation of renal structure and reduced tissue injury. These improvements were accompanied by increased Nrf2, HO-1, and NQO1 mRNA expression and reduced Keap1 expression, suggesting an association with enhanced antioxidant responses. Overall, sustained delivery of WA using the CS/β-GP hydrogel was associated with attenuation of diabetes-associated renal injury and improved renal functional and histological outcomes in this early experimental model. However, the absence of protein-level mechanistic validation and comprehensive pharmacokinetic and tissue-distribution analyses limits definitive conclusions regarding pathway activation and renal targeting. Further studies are warranted to confirm the underlying mechanisms and evaluate long-term therapeutic potential.