The effect of trypan blue on the hepatotoxicity of carbon tetrachloride in the rat

Rats were given intravenous injections of either physiologic saline or trypan blue dye suspended in saline. After 24 hours, the livers of these animals were sampled for light and electron microscopic study. The livers of the saline treated rats showed no morphologic alterations. The livers of the trypan blue injected animals exhibited no structural abnormalities in the hepatic parenchymal cells, but their sinusoidal lining cells were hypertrophied, mainly due to the appearance of numerous phagosomes, increased quantities of rough endoplasmic reticulum, and prominent Golgi zones. Similarly prepared rats were given intraperitoneal injections of CCl₄, 24 hours after the intravenous administration of saline or trypan blue. The livers of these animals were sampled, 24 and 48 hours after the toxic challenge. At both intervals, the livers of the rats treated with trypan blue and CCl₄ displayed far less necrosis and inflammatory reaction than was found in the animals given saline and CCl₄. It was considered unlikely that this difference could be completely explained by changes in hepatic blood flow. It was also demonstrated that, at 24 hours after administration of trypan blue, there were no hepatocellular morphologic alterations that might account for the divergent response to CCl₄. It was proposed, therefore, that the hypertrophied sinusoidal lining cells of the trypan blue treated rats might be related to the observed protection from CCl₄ hepatotoxicity.