Peripheral nerve regeneration in response to target muscular injection of methyl cobalamin in rats

Yaojun LU; Guangxiang HONG

ABSTRACT

BACKGROUND:

Methyl cobalamin, a derivative of vitamin B12, .can promote the metabolism of nucleic acid protein, axoplasmic transport and axonal regeneration.

OBJECTIVE:

To observe the role of target muscular injection of methyl cobalamin ofdifferent dosages in the regeneration of peripheral nerve injury in rats.

DESIGN:

A randomized and controlled animal experiment.

SETTING:

Changzhou Second People's Hospital affiliated to Nanjing Medical University.MATERIALS The experiment was carried out in March 2003. Thirty healthy Wistar rats were randomly divided into three groups with 10 rats in each group high-dosage group, low-dosage group and blank control group.

METHODS:

All the rats were made into models of sciatic nerve injury by epineural suture immediately after transection of left sciatic nerve. Rats in high- and low- dosage groups were injected with methyl cobalamin of 300and 100 μg/kg per day respectively, and those in blank control group were injected with 1 mL normal saline of the same volume, and target muscular injection was given once a day postoperatively. At postoperative 4 and 8weeks, 5 rats were killed at one time; the wet mass of left triceps surae muscle was measured. Morphological observation of sciatic nerve under light and electron microscopes and imaging analysis were made as the detected indexes to analyze the effect of methyl cobalamin of different dosages on sciatic nerve injury in rats.sciatic nerve myelin sheath at postoperative week 8.parison of the wet mass of triceps surae muscle at postoperative 4 weeks It was higher in high-dosage group than in low-dosage group and blank control group [(1.367±0.012) g, (1.164±0.011) g, (0.950±0.009) g, P ＜ 0.05].week 8 It washigher in high-dosage group than in low-dosage group and blank control group [(2.205±0.015), (1.611±0.013), (1.230±0.014) g, P ＜ 0.05].weeks postoperatively It was obviously higher in high-dosage group than in low-dosage group and blank control group [(13.30±1.167), (9.453±1.233),atic nerve myelin sheath at 8 weeks postoperatively It was thicker in highdosage group than in low-dosage group and blank control group [(1.145±0.108),(0.806±0.065), (0.560±0.045) mm, P ＜ 0.05].

CONCLUSION:

Target muscular injection of methyl cobalamin can promote the regeneration of peripheral nerve, and methyl cobalamin of high dosage can better play its role in nourishing injured nerve.