Altered mRNA and protein expression of exosome-related markers in bile duct ligation-induced liver fibrosis in rats.

BACKGROUND: Small extracellular vesicles, including exosomes, are involved in cell-to-cell communication during liver injury and fibrosis. Pathological conditions, such as cholestatic liver injury, may influence the expression of markers associated with extracellular vesicle pathways. This study examined the hepatic mRNA and protein expression of selected exosome-associated markers in a rat model of bile duct ligation (BDL)-induced liver fibrosis. METHODS: Sixteen male Wistar rats were divided into sham-operated and BDL groups (n = 8 per group). Four weeks after surgery, liver tissue was evaluated histologically using hematoxylin and eosin and Masson's trichrome staining. Fibrosis and inflammation were further assessed by Western blot analysis of α-smooth muscle actin (α-SMA) and ELISA measurement of interleukin-1β (IL-1β). Hepatic mRNA levels of Alix, Rab27b, and CD63 were measured using quantitative real-time PCR (qRT-PCR), and their corresponding protein expression was analyzed by Western blotting. RESULTS: BDL induced clear histopathological features of liver fibrosis, including bile duct proliferation, inflammatory infiltration, and collagen accumulation. α-SMA protein expression and IL-1β levels were significantly increased in BDL rats compared with sham controls. Western blot and qRT-PCR analyses revealed significantly increased hepatic expression of Rab27b and CD63 at both the mRNA and protein levels. Alix expression showed an upward trend but did not reach statistical significance at either the mRNA or protein level. CONCLUSION: BDL-induced liver fibrosis is associated with altered hepatic expression of selected exosome-associated markers, particularly Rab27b and CD63. Given that extracellular vesicles were not directly isolated or functionally characterized, these findings should be interpreted as indirect evidence of altered exosome-related pathways rather than direct proof of modulated exosome production or activity. Further studies are required to elucidate the functional role of these markers in the pathogenesis of liver fibrosis.