Change of galactolipids and metabolism of fatty acids in the organotypic culture of myelinating mouse brain.
The concentrations of cerebrosides and sulfatides, myelin-characteristic galactolipids, can be determined in organotypic culture of newborn mouse cerebellum by high-performance liquid chromatography. These galactolipids can be detected at 9-days in vitro explants and increased steadily until the explants were more tan 3 weeks old. The levels of nonhydroxycerebroside, hydroxycerebroside, nonhydroxysulfatide, hydroxysulfatide, and monogalactosyl diacylglycerol were 0.3, 0.6, 0.3, 0.2, and 0.3 nmol/mg protein at 9 days in vitro, respectively, and 1.0, 2.7, 0.9, 0.4, and 0.6 at 21 days in vitro, respectively. When serum was removed from the feeding medium after 9 days, the levels of these lipids did not increase and myelination failed to occur. When a 17 day explant was kept in medium containing [1-14C]lignoceric acid for 4 days, considerable radioactivity was taken up by the explant and incorporated into nonhydroxy- and hydroxycerebrosides, sulfatides and sphingomyelin. Most of the radioactivity in the alpha-hydroxy fatty acids was found in cerebronic acid, the product of lignoceric acid alpha-hydroxylation. Similar explants also took up [1-14C]palmitic acid when it was added to the medium. The radioactivity was, however, mostly incorporated into neutral lipids and glycerophospholipids. These observations indicate that the cultured mouse cerebellum explants synthesize and accumulate myelin-characteristic lipids as does brain in vivo.