A Possible Role of Chenodeoxycholic Acid and Glycine-Conjugated Bile Acids in Fibrotic Steatohepatitis in a Dietary Rat Model

Our previous study indicated that hepatic bile acids (BAs) may have deposited and stimulated the pathogenesis of a high fat-cholesterol (HFC) diet-induced fibrotic steatohepatitis in stroke-prone spontaneously hypertensive 5/Dmcr rats, based on dysregulated BA homeostasis pathways. We aimed to further characterize BA profiles in liver and evaluate their relationships to liver injury using this model. Hepatic 21 BA levels were determined by ultra-performance liquid chromatography-tandem mass spectrometry, and their correlations with macrovesicular steatosis score, serum alanine aminotransferase (ALT) level and quantified fibrotic area were assessed using Spearman and Pearson correlations. Compared to control, BAs highly accumulated in HFC-fed rat liver at 2 weeks: cholic acid (CA), deoxycholic acid (DCA) and chenodeoxycholic acid (CDCA) were major species, thereafter, levels of CA and DCA declined, but CDCA species persistently increased, which induced a decrease in total CA/total CDCA ratio at 8 and 14 weeks. CDCA species positively, while total CA/total CDCA negatively, correlated with macrovesicular steatosis score, serum ALT and quantified fibrotic area. Unlike control, total ursodeoxycholic acid was minor in HFC-fed rat liver, and inversely correlated to aforementioned indicators of liver injury; total glyco-BAs, rather than tauro-BAs, were predominant in HFC-fed rat liver, and positively correlated with macrovesicular steatosis score. Moreover, its ratio to total tauro-BAs positively correlated with each parameter of liver injury, while inverse associations were detected for total tauro-BAs. Hepatic BA accumulation may potentiate liver disease. CDCA and glyco-BAs play a more important role in the pathogenesis of fibrotic steatohepatitis.