No abstract

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 γ-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.

Guinea pigs were given a single intraperitoneal injection of 1.35 mg/kg body weight of mercuric chloride; then various kidney enzymes and extracellular DNA were assayed in urine. Dramatic increases of all studied markers were observed on the first day following treatment. Sequential collection of urines allowed for kinetic studies: membrane markers alkaline phosphatase and γ-glutamyltransferase were first released, then cytosolic lactate dehydrogenase and mitochondrial glutamate dehydrogenase, finally extracellular DNA; DNA release is equated with cell death. The features of kidney damage revealed by comparative and quantitative studies of these noninvasive markers suggest that brush border erasure was more extensive than cell necrosis.