Bromobenzene accelerates hepatocyte streaming in rats

Sixty male adult rats weighing between 250 and 300 g were divided in two equal experimental groups. The first experiment was designed to evaluate hepatocyte streaming. Animals were injected with 0.5 microCi [3H]thymidine and 1 hour later received one intraperitoneal injection of bromobenzene (3.8 mmol/kg, dissolved in corn oil). The animals were then killed in groups of five at 1 hour and 2, 4, 7, 14, and 30 days. The aim of the second experiment was to evaluate labeling index changes with time. Animals received one intraperitoneal injection of bromobenzene and were killed in groups of five at 1, 2, 3, 4, 7, and 14 days. They received [3H]thymidine 1 hour before killing. Bromobenzene induced a necrosis in the third acinus zone that disappeared within a week. On day 0 the labeling index of hepatocytes and littoral cells was 0.3% +/- 0.04% and 0.4% +/- 0.05%, respectively. On the second day, it reached 14.6% +/- 2.6% and 10.1% +/- 3.1% and returned to its initial value after 1 week. Dead cells in the third zone were replaced by inflowing cells from the intact zones. Hepatocytes and littoral cells streamed at the same velocity of 6 +/- 0.5 micron/day, faster than in untreated animals with velocity of 3.2 microns/day. Parenchyma and stroma responded to injury in a coordinated fashion. From the functional point of view, hepatocytes and littoral cells operate as a unit that is called proliferon. The maximal proliferon life span was 57 days after bromobenzene treatment and 108 days in controls.