Adenovirus-mediated overexpression of the activin βc subunit accelerates liver regeneration in partially hepatectomized rats

Background/Aims The expression level of the activin βC subunit is high in normal liver and reduces after partial hepatectomy, but its function is controversial. Methods To determine the role of the βC subunit during liver regeneration, we overexpressed the βC subunit gene in the liver by infusing adenovirus vector encoding the flag-tagged βC subunit into the portal vein. Adenovirus vector encoding the β-galactosidase was also infused as a control. Seventy percent hepatectomy was performed 4 days after the infection. Results Approximately 20% of hepatocytes expressed the flag-tagged βC subunit at the time of hepatectomy and approximately 50% of hepatocytes expressed the βC subunit 3 days after hepatectomy. In βC-infected liver, bromodeoxyuridine labeling was significantly greater at 24 and 48 h after partial hepatectomy compared with the control liver. Consistent with this observation, the liver regeneration rate was significantly greater in βC-transfected liver at 72 and 96 h after hepatectomy. Many of the bromodeoxyuridine-positive nuclei were observed in or by the βC-transfected hepatocytes. Conclusions These results indicate that liver regeneration is accelerated in βC-overexpressing liver. The βC subunit may function to promote replication of hepatocytes during liver regeneration.