Quantitative analysis of myelin and axolemma particle distribution in C57BL/Ks diabetic mice and the effects of ganglioside treatment.

By freeze-fracture technique we estimated myelin and axolemma intramembranous particle density in C57BL/Ks mice. A decrease in myelin particle content compared to controls is present in both 180 and 280 day old genetic diabetic mice. In addition, the axolemma of myelinated axons is affected in interparanodal regions while no modification was detected at nodal level. Such alterations of myelin membrane structure may also be responsible for the lower motor nerve conduction velocity (MNCV) observed in these diabetic mice; however this hypothesis cannot be taken into consideration for the reduction in MNCV at the early stage of the neuropathy (prior to 180 days of life). Therefore the structural changes of both myelin sheath and interparanodal axolemma as visualized by freeze-fracture are most likely related to late complications of the disease instead of being responsible for the changes in excitability. The low myelin and axolemma particle density of diabetic mice was found normal after 30 days' treatment with gangliosides. Such findings are in agreement with previous results on a significant effect of ganglioside treatment on MNCV and axonal area alterations in 180 and 280 day old genetic diabetic mice.