Establishment of a Diet-Induced Systemic Metabolic SyndromeModel Reveals Early Renal Alterations and the Nephroprotective Potential of Three Jabuticaba (Myrciaria cauliflora) Formulations

Abstract Metabolic syndrome is a progressive disorder associated with metabolic dysregulation, insulin resistance, chronic inflammation, and increased risk of chronic kidney disease. The kidney is an early target of metabolic imbalance, developing structural alterations before the establishment of advanced renal dysfunction. Jabuticaba ( Myrciaria cauliflora ), a Brazilian berry rich in phenolic compounds, has emerged as a promising functional food, and technological strategies such as microencapsulation may improve the stability and potential biological effects of its bioactive compounds. This study evaluated the effects of three jabuticaba formulations—freeze-dried whole fruit, freeze-dried peel, and microencapsulated peel extract—on renal morphology, relative elemental composition, and oxidative status in mice subjected to a high-fat, high-fructose (HFHF) diet. Fifty male C57BL/6 mice were allocated into five groups ( n = 10): Control, HFHF, HFWF (HFHF + whole fruit), HFJP (HFHF + peel), and HFME (HFHF + microencapsulated peel extract). After six weeks of metabolic challenge, jabuticaba was introduced while maintaining the HFHF diet for an additional six weeks. At the end of the 12-week experimental period, kidneys were collected for morphometric, histopathological, elemental, and oxidative analyses. The HFHF diet induced early renal alterations characterized by increased vascular proportion, reduced tubular proportion, vascular congestion, tubular vacuolization, and inflammatory cell infiltration, indicating early renal structural changes associated with HFHF-induced metabolic dysfunction. Jabuticaba addition produced formulation-dependent effects on renal morphology, with the microencapsulated peel extract showing the most consistent histological preservation. The HFHF diet also altered the renal elemental profile, increasing the relative proportions of calcium and manganese and reducing sodium compared with Control animals. Among the Jabuticaba groups, HFWF shifted calcium and sodium proportions toward Control values, whereas HFJP and HFME maintained the HFHF-associated pattern for these elements. For manganese, HFJP and HFME showed intermediate values that did not differ significantly from either Control or HFHF animals. No significant differences were observed among groups for oxidative stress markers (malondialdehyde, protein carbonyls, nitric oxide, and FRAP) or antioxidant enzymes (catalase, superoxide dismutase, and glutathione S-transferase), indicating that the observed morphological and elemental disturbances were not accompanied by detectable changes in renal oxidative stress biomarkers or antioxidant defenses. Thus, the effects associated with jabuticaba should not be interpreted as primarily antioxidant-mediated. These findings indicate that Myrciaria cauliflora addition in HFHF diet was associated mainly with preservation of renal histological architecture and modulation of the relative elemental profile in a formulation-dependent manner, with the microencapsulated peel extract showing the most consistent histological effects. The results highlight the potential of jabuticaba peel valorization and microencapsulation technology as strategies for developing functional ingredients aimed at preserving renal tissue during early metabolic dysfunction, although further functional and molecular studies are required to confirm nephroprotective effects.