Biochemical and pathological studies of myelin in hexachlorophene intoxication

Abstract

Adult female rats were fed a diet containing 500 ppm hexachlorophene (HCP). Morphological study of brains from these animals showed vacuolation of the myelin sheaths due to separation of myelin lamellae at the minor dense line. However, myelin could be isolated from the brains of these animals in normal yield. The myelin isolated from HCP-fed animals had normal lipid and protein compositions as shown by analyses of the individual lipids and by disc gel electrophoresis of the proteins. Assay of the myelin-specific enzyme, 2',3'-cyclic nucleotide-3'-phosphohydrolase, showed normal specific activity in myelin obtained from HCP-fed rats. Brains of HCP-fed rats showed an increase in wet weight and a decrease in dry weight, with the chloroform-methanol insoluble fraction showing the greatest weight loss. During isolation of myelin from HCP-fed rats material was found floating over 0.32 M sucrose. This "floating fraction" contained a higher ratio of lipid to protein but the same relative proportions of the individual lipids as are found in myelin. The yield of "floating fraction" from each HCP-fed rat was less than 10 percent of the yield of myelin. Disc gel electrophoresis demonstrated the presence of the usual myelin proteins in this fraction, but with a slight increase in the relative amount of the low molecular weight basic protein. The data were compared to reports on the biochemistry of triethyltin poisoning, and it was concluded that vacuolation of myelin in HCP poisoning is probably due to increased permeability of myelin lamellae to water and electrolytes.