The expression of
neutral glycosphingolipids (GSLs) and
gangliosides was investigated in cryosections of normal mouse skeletal muscle and in muscle of mice with
neuromuscular diseases using indirect immunofluorescence microscopy. Transversal and longitudinal sections were immunostained with specific polyclonal
antibodies against
lactosylceramide,
lacto-N-neotetraosylceramide, globoside, GM3(Neu5Ac), GM3(Neu5Gc) and Gm1(Neu5Ac) as well as monoclonal anti-Forssman GSL antibody. In normal CBA/J mouse muscle (control) the main immunohistochemically detected
ganglioside was GM3(Neu5Ac) followed by moderately expressed GM3(Neu5Gc) and GM1. The neutral GSLs
lactosylceramide and globoside were stained with almost identical, high fluorescence intensity. Low amounts of
lacto-N-neotetraosylceramide and trace quantities of Forssman GSL were immunostained. All GSLs were detected in the sarcolemma, but also in considerable amounts at the intracellular level. Mice with
neuromuscular diseases were the A2G-adr mouse mutant (a model for human recessive
myotonia of Becker type), the BL6-wr mutant (a model for
motor neuron disease) and the BL10-mdx mouse mutant (a model for human
Duchenne muscular dystrophy). No changes in GSL expression were found in the A2G-adr mouse, while muscle of the BL6-wr mouse showed increased intensity of immunofluorescence in stainings with anti-
lactosylceramide and anti-GM3(Neu5Ac)
antibodies. Muscle of BL10-mdx mice showed the most prominent changes in GSL expression with reduced fluorescence intensity for all
antibodies. Major differences were not observed in the intensities of GSLs, but there were significant differences in the patterns of distribution on plasma membrane and at the subcellular level. The exact nature and pathogenesis of these changes should be elucidated since such investigations could furnish advances in understanding the functional role of neutral GSLs and
gangliosides in normal as well as in diseased muscle.