Phloretin mitigates oxidative injury, inflammation, and fibrogenic responses via restoration of autophagic flux in in vitro and preclinical models of NAFLD

Abstract

Nonalcoholic fatty liver disease (NAFLD) with growing incidences is a major health concern worldwide. Alteration in cellular redox homeostasis and autophagy plays a critical role in the progression of NAFLD to more severe outcomes. The lack of safe and effective therapy for the disease necessitates the exploration of new therapeutic compounds. Therefore, in the present study, we investigated the potential of phloretin to maintain redox equilibrium and prevent disease progression via modulation of autophagy in NAFLD. Free fatty acid exposed Huh7 cells were used to evaluate the efficacy of phloretin in vitro. Further, phloretin was administered orally to western diet induced NAFLD in C57BL/6J mice at different doses. The chronic exposure to fatty acids and the western diet triggered lipid accumulation in the Huh7 cells and western diet-fed mice liver, respectively. In addition, mitochondrial dysfunction, oxidative stress, inflammation and decreased hepatic autophagy were observed in disease condition. Phloretin encouraged autophagy mediated hepatic lipid clearance and restored mitochondrial membrane potential and redox homeostasis. It also reduced histological injury by reducing hepatic lipogenesis and facilitating fatty acid oxidation. Moreover, findings of the study also revealed the mitigatory effect of phloretin on inflammatory and fibrogenic markers. Altogether, the study suggested that phloretin effectively attenuates NAFLD progression via upregulating autophagy-mediated lipid breakdown and inhibits oxidative damage, hepatic inflammation and fibrosis.