Zileuton Attenuates Acute Kidney Injury in Glycerol-Induced Rhabdomyolysis by Regulating Myeloid-Derived Suppressor Cells in Mice.

Rhabdomyolysis is characterized by the breakdown of skeletal muscle tissue, frequently leading to acute kidney injury (AKI). Traditional conservative treatments have shown limited effectiveness in modifying the disease course, thereby necessitating targeted pharmacological approaches. Zileuton (Z), a selective inhibitor of 5-lipoxygenase (5-LOX), has demonstrated efficacy in enhancing renal function recovery in animal models of AKI induced by agents such as cisplatin, aminoglycosides, and polymyxins. The present study aimed to evaluate the therapeutic potential of a single dose of Z in mitigating rhabdomyolysis-induced AKI (RI-AKI) via modulation of myeloid-derived suppressor cells (MDSCs). Male C57BL/6 mice were assigned to four experimental groups: Sham (intraperitoneal administration of 0.9% saline), Z (single intraperitoneal injection of Z at 30 mg/kg body weight), glycerol (Gly; single intramuscular dose of 50% glycerol at 8 mL/kg), and glycerol plus Z (Z + Gly; concurrent administration of glycerol intramuscularly and Z intraperitoneally). Animals were sacrificed 24 h post-glycerol injection for analysis. Zileuton administration significantly improved renal function, as indicated by reductions in blood urea nitrogen (BUN) levels (129.7 ± 17.9 mg/dL in the Gly group versus 101.7 ± 6.8 mg/dL in the Z + Gly group, < 0.05) and serum creatinine (Cr) levels (2.2 ± 0.3 mg/dL in the Gly group versus 0.9 ± 0.3 mg/dL in the Gly + Z group < 0.05). Histopathological assessment revealed a marked decrease in tubular injury scores in the Z + Gly group compared to the Gly group. Molecular analyses demonstrated that Z treatment downregulated mRNA expression of macrophage-inducible C-type lectin (mincle) and associated macrophage infiltration-related factors, including Areg-1, Cx3cl1, and Cx3CR1, which were elevated 24 h following glycerol administration. Furthermore, the expression of NLRP-3, significantly upregulated post-glycerol injection, was attenuated by concurrent Z treatment. Markers of mitochondrial biogenesis, such as mitochondrial DNA (mtDNA), transcription factor A mitochondrial (TFAM), and carnitine palmitoyltransferase 1 alpha (CPT1α), were diminished 24 h after glycerol injection; however, their expression was restored upon simultaneous Z administration. Additionally, Z reduced protein levels of BNIP3, a marker of mitochondrial autophagy, while enhancing the expression of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), suggesting that Z ameliorates RI-AKI severity through the regulation of mitochondrial quality control mechanisms. Zileuton also decreased infiltration of CD11b(+) Gr-1(+) MDSCs and downregulated mRNA levels of MDSC-associated markers, including transforming growth factor-beta (TGF-β), arginase-1 (Arg-1), inducible nitric oxide synthase (iNOS), and iron regulatory protein 4 (Irp4), in glycerol-injured kidneys relative to controls. These markers were elevated 24 h post-glycerol injection but were normalized following concurrent Z treatment. Collectively, these findings suggest that Zileuton confers reno-protective effects in a murine model of RI-AKI, potentially through modulation of mitochondrial dynamics and suppression of MDSC-mediated inflammatory pathways. Further research is warranted to elucidate the precise mechanisms by which Z regulates MDSCs and to assess its therapeutic potential in clinical contexts.