Behavior of collagen extracellular liver matrix during regenerative growth after partial hepatectomy or after stimulation by exogenous hepatotrophic factors. Study in rats.

During regeneration after partial hepatectomy, the hepatic parenchyma grows by reproducing its histological elements at different rates. The hepatic cells grow more rapidly and the collagen components of the extracellular matrix more slowly. This report studies the behavior of liver tissue collagen in intact livers, increased in size by stimulation with exogenous hepatotrophic factors, comparing them to regenerated livers after hepatectomy. The series consists of a group of rats (n = 4), seven days after 70% hepatectomy, with an average growth of the residual liver mass of 71.55% and another group (n = 4), seven days after stimulation of the intact livers with an average growth of 121.05%. The exogenous hepatotrophic factors administered intraperitoneally (portal) included glucose, amino acids, insulin, glucagon and triiodothyronine. The hepatic collagen content was compared by studying slides stained with Picrossirius and examined with an optical microscope attached to a computer with an image analyzing program. The hepatic collagen was reduced from 2.07% +/- 0.13 to 1.14 +/- 0.08 (a difference of 44.57%; P < 0.001) after hepatectomy and from 1.98% +/- 0.19 to 1.24% +/- 0.07 (difference of 37.46%; P < 0.01) after exogenous hepatotrophic factors stimulation. It was concluded that the production of collagen in hepatic growth initiating with intact livers stimulated by exogenous hepatotrophic factors, occurs with a time difference similarly to what is observed after 70% hepatectomy.