Metronidazole enhances steatosis-related early-stage hepatocarcinogenesis in high fat diet-fed rats through DNA double-strand breaks and modulation of autophagy

Abstract

Nonalcoholic fatty liver disease is a hepatic disorder with deposition of fat droplets, and has a high risk of progression to steatosis-related hepatitis and irreversible hepatic cancer. Metronidazole (MNZ) is an antiprotozoal and antimicrobial agent widely used to treat patients infected with anaerobic bacteria and intestinal parasites; however, MNZ has also been shown to induce liver tumors in rodents. To investigate the effects of MNZ on steatosis-related early-stage hepatocarcinogenesis, male rats treated with Nnitrosodiethylamine following 2/3 hepatectomy at week 3 were received a control basal diet, high fat diet (HFD), or HFD containing 0.5% MNZ. The HFD induced obesity and steatosis in liver, accompanied by altered expression of Pparg and Fasn, genes related to lipid metabolism. MNZ increased nuclear translocation of lipid metabolism-related transcription factor peroxisome proliferator-activated receptor gamma in hepatocytes, together with altered liver expression of lipid metabolism genes (Srebf1, Srebf2, Pnpla2). Furthermore, MNZ signi cantly increased the number of preneoplastic liver foci, accompanied by DNA double-strand breaks and late-stage autophagy inhibition, as re ected by increased levels of γ-H2AX, LC3, and p62. Therefore, MNZ could induce steatosis-related hepatocarcinogenesis by inducing DNA double-strand breaks and modulating autophagy in HFD-fed rats.

Flutamide exacerbates steatosis and promotes early hepatocarcinogenesis in high-fat diet-fed non-obese steatotic rats: Insights from clustering analysis of mitophagy regulators AMBRA1 and LC3

“…The consumption of HFD induced a signi cant increase in the number and area of GST-P-positive foci (Fig. 1g, 1h, 1k), as previously reported [28][29][30][31] . A previous study showed that that higher FL doses (1000 and 2000 ppm) enhanced hepatocarcinogenesis in rats 27 ; however, in the present study, a lower FL dose (500 ppm) caused a marginal increase in both the number and area of GST-P-positive foci (Fig.…”

“…1a, Table 1). Previous studies have shown that an HFD increases NAS and steatosis scores in the liver [28][29][30][31] . Similar results were obtained in the present study, where FL further increased these scores (Fig.…”

“…In a previous study conducted in our laboratory, FL was observed to enhance precancerous lesions in a medium-term liver carcinogenesis rat model; however, the underlying mechanism remains unclear 27 . In this study, we hypothesized that FL induces mitochondrial injury followed by mitophagy in an HFD-mediated early hepatocarcinogenesis model [28][29][30][31] . This model, based on the medium-term hepatocarcinogenesis assay 32 , served as a valuable tool for understanding the augmentation of autophagy in precancerous lesions facilitated by fatty liver conditions [28][29][30][31] .…”

“…In this study, we hypothesized that FL induces mitochondrial injury followed by mitophagy in an HFD-mediated early hepatocarcinogenesis model [28][29][30][31] . This model, based on the medium-term hepatocarcinogenesis assay 32 , served as a valuable tool for understanding the augmentation of autophagy in precancerous lesions facilitated by fatty liver conditions [28][29][30][31] . This model is particularly advantageous since hepatic precancerous lesions speci cally express the autophagosome marker LC3 and the cargo receptor p62 29,31,33 .…”

“…This model, based on the medium-term hepatocarcinogenesis assay 32 , served as a valuable tool for understanding the augmentation of autophagy in precancerous lesions facilitated by fatty liver conditions [28][29][30][31] . This model is particularly advantageous since hepatic precancerous lesions speci cally express the autophagosome marker LC3 and the cargo receptor p62 29,31,33 . Using immunohistochemical techniques and cluster analysis using autophagy markers, we investigated the role of autophagy in small precancerous lesions in rat livers 34 .…”