Protective effects of astaxanthin solid lipid nanoparticle as a promising candidate against acute kidney injury in rats.

Acute kidney injury (AKI) is a sudden onset of renal injury that occurs within a few hours or days. Ischemia-reperfusion (IR) is a major cause of AKI. There are multiple dysregulated mechanisms behind the pathogenesis of AKI and IR which urges the need for finding multi-targeting therapies. Natural products are multi-targeting agents with promising sources of anti-inflammation, antioxidant, and antiapoptosis. Among them, astaxanthin (AST) is a keto-carotenoid with a high antioxidant potential. Using solid lipid nanoparticles (SLNs) as a novel formulation of AST helps to increase its efficacy and reduce side effects against AKI. After SLN preparation and loading of AST, the physicochemical properties were evaluated, using scanning electron microscopy (SEM) and dynamic light scattering (DLS) tests. For the in vivo study, 28 rats were divided into four groups, including sham, ischemia/reperfusion (I/R), and groups receiving protective and daily doses of AST-SLN (5 and 10 mg/kg, i.p.) during all 5 days before ischemia. Exactly 24 h after ischemia, kidneys were isolated for histological studies, and also, serum levels of catalase (CAT), glutathione (GSH), nitrite, blood urea, and creatinine were measured. The results indicated that intraperitoneal administration of SLN-AST reduced oxidative stress by decreasing serum nitrite levels, while increasing CAT and GSH. SLN-AST also improved renal function by decreasing serum urea and creatinine and preventing tissue damage. Therefore, SLN-AST could be a hopeful adjuvant candidate to prevent AKI by modulating renal function, preventing tissue damage, and through antioxidant mechanisms.