Effects of hexachlorophene on myelin marker enzymes in rat oligodendrocytes

Abstract

The antibacterial substance hexachlorophene (HCP) can affect myelin formation or integrity leading to intramyelinic oedema and vacuolation in the central nervous system through an unknown mechanism. These studies were conducted to investigate the direct, dose-dependent effects of HCP on myelin membrane markers in cultured oligodendrocytes (OLG) isolated from 4–7-day-old rat pups and cultured in vitro for up to 5 wk. 2-wk-old OLG cultures were exposed to 0, 0.24 or 0.74 μ m HCP for 48 hr. At 48 hr and again at 5, 12 and 19 days after the end of dosing the myelin markers galactosylceramide (GalC), myelin basic protein (MBP), and 2′,3′-cyclic nucleotide 3′-phosphohydrolase (CNPase) were quantified by ELISA or biochemical techniques. DNA was measured to estimate total cell mass and astrocyte contamination was determined by an ELISA procedure using anti-glial fibrillary acidic protein (GFAP) as the primary antibody. Because of the use of a selective culture medium, astrocyte contamination was initially low and continued to decrease from wk 2 to 4 as determined by GFAP binding. CNPase, GalC and MBP levels were similar in control and low-dose (0.24 μ m HCP) cultures with a general increase in MBP and CNPase over time. Cultures exposed to 0.74 μ m HCP showed a decline in GalC proportional to decreased DNA content with time, but levels of MBP and CNPase increased after dosing and were always greater than the corresponding levels in control or low-dose cultures. These studies suggest a direct, dose-related toxic effect of HCP accompanied by a stimulation of MBP and CNPase but not of GalC production in the membranes of the recovering OLG following removal of HCP.