Quantitative Analysis of the Effect of Methylcobalamin on the Peripheral Nerve Structures in Experimental Diabetic Neuropathy

Abstract

To study in vivo effect of methylcobalamin (CH₃-B₁₂) on the peripheral nerve structures, rats with experimental diabetes induced by streptozotocin were administered with daily intramuscular injection of CH₃-B₁₂ (500μg/kg). Improved general conditions such as an increase in body weight or ameliorated glucose intolerance were observed in the diabetic rats treated continuously with CH₃-B₁₂ for 16 weeks.
There were no definite morphometrical differences between the diabetic rats treated with CH₃-B₁₂ only for 8 weeks during the latter half of this experiment, and non-treated iabetic rats. However, the diabetic rats continuously treated with CH₃-B₁₂ for 16 weeks showed low incidence of degenerated nerve fibers and less reduction of myelinated nerve fiber density than those of npn-treated diabetic rats (p<0.01 and p<0.05).
The reduction of myelinated nerve fibers predominantly of large diameter (5-8μ) were prevente in the treated diabetic rats in contrast with those of nontreated diabetic rats on the histograms of the diameter of myelinated nerve fibers.
The results suggested that an early continuous treatment with CH₃-B₁₂ inhibited the evolution of peripheral nerve lesions in rats with experimental diabetes.