Enhanced Prophylactic Nephroprotective Effects of Nanoliposomal Nootkatone Against Cisplatin-Induced Renal Injury: Associations with NRF2/HO-1, TLR4/NF-κB, Apoptosis-Related (Bax/Bcl-2/Caspase-3), and Ferroptosis-Related (GPX4/SLC7A11) Markers.

This study investigated the prophylactic nephroprotective effects of crude nootkatone (NKT) and its nanoliposomal formulation (NKT-LNPs) against cisplatin-induced renal injury in rats. Sixty male Sprague-Dawley rats were randomly allocated into six groups: control, NKT, NKT-LNPs, cisplatin, cisplatin + NKT, and cisplatin + NKT-LNPs. NKT or NKT-LNPs (10 mg/kg NKT equivalent) was administered orally as prophylactic treatment for 7 days, with a single cisplatin injection (7.5 mg/kg, i.p.) on day 7. Renal function, oxidative/nitrosative stress, antioxidant defense, inflammation-associated markers, apoptosis- and ferroptosis-associated markers, histopathological, and ultrastructural alterations were evaluated. Cisplatin markedly impaired renal function, as evidenced by elevated serum urea, creatinine, uric acid, KIM-1, and NGAL levels. It also induced oxidative stress by increasing ROS, MDA, and NO, while decreasing NRF2/HO-1-associated markers and reducing GSH, GPX, SOD, and CAT activities. In parallel, cisplatin increased TLR4/NF-κB-associated inflammatory markers, including TNF-α, IL-6, and IL-1β levels. Apoptosis-associated alterations included increased Bax, total caspase-3, and whole-tissue cytochrome-c levels, together with reduced Bcl-2 and total AKT protein abundance. Furthermore, cisplatin produced ferroptosis-associated changes, including increased iron accumulation, TFR1, ACSL4, and 4-HNE, alongside reduced GPX4 and SLC7A11 levels. Histopathological and ultrastructural analyses revealed severe renal damage. Prophylactic administration of both NKT and NKT-LNPs significantly ameliorated cisplatin-induced alterations, with the complete NKT-LNP formulation providing greater protection than free NKT under the tested conditions, restoring biochemical, molecular, and structural parameters toward normal levels. These findings show that NKT-LNPs were associated with greater nephroprotection than crude NKT, together with favorable changes in oxidative stress, inflammatory, apoptosis-associated, and ferroptosis-associated markers. Overall, the NKT-LNP formulation demonstrated promising prophylactic nephroprotective effects against cisplatin-induced renal injury; however, the absence of a blank-liposome control prevents attributing its greater protective effects specifically to nanoencapsulation or excluding potential contributions from the lipid carrier.