Styrene hepatotoxicity in rats treated by inhalation or intraperitoneally: a structural investigation.

The purpose of this study was to investigate the toxicity of styrene in the liver of adult rats treated either by inhalation of styrene vapour (300 ppm, 6 h/d, 5 d/wk, for 2 wk) or intraperitoneally with different styrene doses (4, 40, 400 mg/Kg) for 3 consecutive days. Using a light microscope, some alterations of liver parenchyma and sinusoid dilation were noticed, more marked in the group treated with the intraperitoneal administration of the chemical. Using an electron microscope, some additional changes were observed (once again, more marked in the latter group of rats): a) an increase in the content of lipids inside hepatocytes, and b) the rise of intracytoplasmic, intercellular and perisinusoidal collagen fibres. Therefore, cell damage and functional disturbance of sinusoids due to perisinusoidal fibrosis are apparent in the liver of both groups of rats exposed to styrene treatment, but these changes are definitely more significant in those subjected to intraperitoneal administration.