Abstract

Aspartame, a widely used artificial sweetener, has raised concerns regarding its potential hepatotoxicity under chronic exposure. This study aimed to investigate the protective roles of phenylboronic acid (PBA) and exosomes (Exo) againist chronic aspartame-induced liver injury in male BALB/c mice through modulation of the TGF-β-Smad/REDD1 signaling pathways. Mice were divided into seven groups: Control, Exo, PBA, aspartame (Asp), and treatment groups receiving PBA, Exo, or their combination following aspartame exposure. Liver tissues were collected for histopathological, immunohistochemical, and western blot analyses. Chronic aspartame administration resulted in marked hepatocellular degeneration, inflammatory infiltration, and architectural disorganization. Moreover, aspartame exposure significantly increased Smad2/3 and decreased REDD1 protein expression levels, indicating activation of pro-fibrotic and stress-related signaling pathways. The number of TGF-β, TNF-α, MMP-9, and caspase-3 positive cells was elevated in the Asp group. Consistent with these findings, immunohistochemical results demonstrated reduced hepatic stellate cell (HSC) activation, decreased apoptosis, and improved tissue morphology in treated groups. Additionally, treatment with PBA and Exo attenuated TGF-β activation while upregulating REDD1 expression. These findings highlight that PBA, Exo, and their combination exert remarkable hepatoprotective effects by modulating the TGF-β-Smad and REDD1 pathways, providing a promising therapeutic strategy againist chronic aspartame-induced liver injury.