Differential regenerative response and expression of growth factors following hepatectomy of variable extent in rats

Liver regeneration is a physiological mechanism which leads to restoration of the hepatic parenchyma following hepatectomy or toxic injury. This process is mediated by a wide variety of cytokines and growth factors. The aim of the present study was to evaluate the influence of hepatectomy extent on the levels of intrahepatic mRNAs for cell-cycle markers and growth factors in rats submitted to a 30%, two-third or 80% hepatectomy.

Cyclins, thymidine kinase and growth factors mRNA levels were quantitatively assessed by RT-PCR at different time points post-hepatectomy (2h, 6h, 12h, days 1, 2, 6).

As compared with a two-third hepatectomy, cyclins and thymidine kinase mRNA levels were increased but with a delayed peak at day 2 in the 80% hepatectomy group and showed a progressive increase until day 6 in the 30% hepatectomy group; mRNA levels for HGF or TGFalpha were increased with a delayed peak at 12 h or day 2 in the 80% hepatectomy group, respectively and this delay was more pronounced in the 30% hepatectomy group with a peak at day 1 or day 6.

A regenerative response occurs whatever the extent of hepatectomy but the course of regeneration and expression of growth factors differs according to the volume of resected liver. A better knowledge of these events could improve the clinical results of hepatic resection for primary or metastatic liver disease.