The Morphometric changes of Rat Peripheral nerve after Methyl-cobalamin Treatment in Capsaicin Induced Neuropathy

ABSTRACT

BACKGROUND: Methcobalamin was known to act as a methyl donor in DNA metabolism and increase Protein synthesis for nerve regeneration. To determine whether methylcobalamin affects capsaicin induced polyneuropathy in rat sural nerves. METHODS: On their second day of life, 18 newborn rats were injected subcutaneously with capsaicin(50mg/kg). Ten rats were treated with methylcobalamin(500microgram/kg) and eight rats with normal saline 5 days a week for 12weeks after capsaicin injection. Using morphometry and computer digitization, the number and sloe distribution of myelinated and unmyelinated fibers were evaluated in sural nerves at 13 weeks. RESULTS: There was significant difference in the number of unmyelinated fibers between two groups(control group 33,321 +/- 15,539/mm2; methylcobalamin group 99,614+/-20,581/mm2. p<0.0001). Methylcobalamin did not change the number and size distribution of'myelinated fibers. The size distribution of'unmyelinated fibers was approximately the same. CONCLUSIONS: This study suggested that methylcobalamln could increase regeneration of peripheral nerve morphometrically. It appears that methylcobalamin might be one of the useful therapeutic agents in various polyneuropathies.