Abstract
The effect of daily administration of vitamin B derivatives on the sciatic nerve of alloxan diabetic rats was examined. Diabetic rats were kept on restricted intake of vitamin B_1, B_6 and B_<12> for 5 weeks beginning one week after alloxan administration and then received intraperitoneal injection of vitamin B derivatives for 4 weeks. The diabetic rats without vitamin B derivative administration showed decreased motor nerve conduction velocity (MNCV), slight atrophy of Schwann cells and disintegration of myelin sheath of the sciatic nerves. Administration of thiamine tetrahydrofurfuryl disulfide (TTFD) (2mg/kg/day), pyridoxal phosphate (PLP) (2mg/kg/day) and hydroxycobalamin (OH-B_<12>) (40μg/kg/day) to the diabetic rats resulted in normalization of the function and structure of the nerve. Neither PLP nor OH-B_<12> had an effect on the function and structure of the nerve. Administration of TTFD alone at doses higher than 35.9μg/kg/day ameliorated the function, but not the structure of the sciatic nerve. However, when injected with PLP and OH-B_<12>, subeffective doses of TTFD (8.97 and 17.95μg/kg/day) had the ameliorative effect on the nerve function .These results suggest that TTFD has ameliorative effects potentiated by PLP and OH-B_<12> on the sciatic nerve of alloxan diabetic rats.
