TRANSFORMING-GROWTH-FACTOR-ALPHA (TGF-ALPHA) EXPRESSION CORRELATES WITH DNA-REPLICATION IN REGENERATING RAT-LIVER WHATEVER THE HEPATECTOMY EXTENT

Liver regeneration is a physiological mechanism that leads to restorat ion of the hepatic parenchyma following hepatectomy or toxic injury. A s a two-third hepatectomy is the usual model to analyse this phenomeno n, few studies have compared liver regeneration after minor vs major h epatectomy. We have used a quantitative RT-PCR technique to study the hepatic transcription of the TGF-alpha gene in rats submitted to 30% o r 80% hepatectomy, and we have correlated this transcription with the regenerative response assessed by flow cytometry and Ki-67 expression. The level of TGF-alpha expression and the regenerative response were different, according to the volume of liver removed, and were statisti cally correlated (r=0.679, p=0.002). TGF-alpha expression and phase S peaked at day 2 vs 6 in the 80% vs 30% hepatectomized rat groups, resp ectively. Ki-67 expression occurred at 2 h post-hepatectomy in the two groups of rats and was observed until day 14 mainly in the 80% hepate ctomy group. Our results indicate that TGF-alpha expression in regener ating liver is strongly correlated with hepatocyte mitosis, that a del ayed regenerative response occurs following 30% hepatectomy and that t he course of regeneration differs between minor vs major hepatectomy.