Dietary Ammonium Hydroxide Enhancement Modulates Renal Inflammatory and Apoptotic Signaling and Mitochondrial-Associated Pathways in High-Fat-Fed C3H/HeJ Mice

Diet-induced obesity contributes to chronic inflammation, mitochondrial dysfunction, and progressive kidney injury, while increased dietary acid load may further impair renal homeostasis. In our previous studies, we showed that ammonium hydroxide enhancement (AHE) of dietary protein, prior to incorporation into the complete diet, increases dietary alkalinity and has improved longevity, decreased secretion of adipocytokines, and beneficially affected the microbiome in high-fat diet fed C3H/HeJ mice. However, its effects on renal molecular and structural responses remain unknown. In this study, kidney tissues from male C3H/HeJ mice fed control casein (CC), ammonium hydroxide-enhanced casein (CCN), high-fat casein (HFC), ammonium hydroxide-enhanced high-fat casein (HFCN), high-fat beef (HFB), or ammonium hydroxide-enhanced high-fat beef (HFBN) diets were analyzed using quantitative PCR, Western blotting, and histological morphometry. Results showed that AHE reduced renal inflammatory signaling, evidenced by decreased TLR4, TNFα, Il1-β, IL6, and NFκB expression. Apoptosis-associated signaling was attenuated through reduced Caspase-3 and p53 expressions and increased BCL2 levels. AHE also modulated mitochondrial-associated markers. Increased markers of mitochondrial biogenesis and fusion, and decreased fission-associated markers were observed, along with increased PINK1 expression, while Parkin remained unchanged. In addition, expression levels of the ammonia transporters, RHBG and RHCG, were elevated, indicating altered renal ammonia transporter expression. Histological and morphometric analyses demonstrated AHE-associated changes in tubular areas, while glomerular and Bowman’s capsule areas remained largely unchanged. Collectively, these findings suggest that long-term dietary AHE is associated with alterations in renal inflammatory and apoptotic signaling, mitochondrial-associated pathways, ammonia transporter expression, and renal histomorphometry in male C3H/HeJ mice.