Liver enzyme changes in a guinea-pig model of facial eczema (sporidesmiotoxicosis).

Sporidesmin, a hepatotoxin from Pithomyces chartarum, is responsible for facial eczema in ruminants. In an attempt to clarify the biochemical processes supporting sporidesmin toxicity and response of the liver, haematology, plasma biochemistry and liver enzyme changes were monitored for 21 days in a model for facial eczema resulting from a single intraperitoneal injection of 2.8 mg/kg BW sporidesmin to guinea pigs. Most plasma disturbances were observed 8 days after administration and accounted for starvation, liver cytolysis, and cholestasis or liver enzyme induction. Alterations of hepatic enzyme activities were intense with a maximum increase on days 2 for alkaline phosphatases (ALP) and 8 for gamma-glutamyltransferase (GGT), and a maximum decrease on day 21 for aspartate aminotransferase (ASAT) and alanine aminotransferase (ALAT). Comparison of liver and plasma enzyme changes indicates that GGT was the most reliable and significant plasma indicator of sporidesmin-associated liver alterations. Moreover, this study points out the validity of the one-dose intoxicated guinea-pig model for research on sporidesmin biochemical toxicity and pathobiology of facial eczema.