Comparative evaluation of the electrophysiological, functional and ultrastructural effects of alpha lipoic acid and cyanocobalamin administration in a rat model of sciatic nerve injury.

BACKGROUND: Vitamin B12 and alpha lipoic acid (ALA) are known to promote functional and morphological recovery after peripheral nerve injury. OBJECTIVE: To compare the regenerative and neuroprotective effects of vitamin B12 and ALA treatment after sciatic nerve injury. METHODS: A total of 40 rats were randomly assigned to control (sciatic nerve exposure without injury or anastomosis), sham (sciatic nerve injury and epineural anastomosis were performed but no treatment was administered), PS (isotonic saline was administered for 12 weeks after surgery), ALA (2 mg/kg ALA was administered for 12 weeks after surgery), and vitamin B12 groups (2 mg/kg cyanocobalamin was administered for 12 weeks after surgery). Functional recovery was determined by footprint analysis, in vivo neurophysiology, and ex vivo histopathological examination. RESULTS: ALA treatment produced significant improvements in sciatic functional index values and non-significant improvements on electroneuromyography compared to vitamin B12 treatment. Upon histopathological examination, the regenerative effects of ALA were relevant to axonal structural recovery whereas vitamin B12 produced greater improvements in edema and myelination. CONCLUSIONS: While both vitamin B12 and ALA produced improvements after sciatic nerve injury, ALA was more functionally effective. The unique ultrastructural effects of vitamin B12 and ALA treatment should be considered in future studies.

An evaluation of the effectiveness of pre-ischemic hyperbaric oxygen and post-ischemic aminoguanidine in experimental cerebral ischemia.

OBJECTIVE: To study the effects of pre-ischemic hyperbaric oxygen (HBO) and post-ischemic aminoguanidine (AG) on the infarct volume in permanent middle cerebral artery occlusion. METHODS: This study was approved by the Animal Experiments Ethics Committee of Gulhane Military Medical Academy, Ankara, Turkey and carried out from March 2006 to August 2006. A total of 28 Sprague-Dawley rats (200-320 g) were divided into 4 groups: control (K) group (n = 7); HBO group (n = 7); HBO + AG group (n = 7); and the AG group (n = 7). All rats underwent middle cerebral artery occlusion (MCAO) by subtemporal craniectomy, and permanent ischemia was created. A 2.8 atmospheric pressure of HBO was first applied to the HBO and HBO + AG groups for 45 minutes, and occlusion was created after 2 hours. In the HBO + AG group, intraperitoneal administration of AG hemisulfate (100 mg/kg) was started 6 hours after MCAO, and was continued twice a day for 3 days. RESULTS: The rate of infarction was found to be 22.2+/-3.1% in the control group, 16.1+/-2.7% in the HBO group, 15.2+/-1.9% in the HBO+AG group, and 14.4+/-3.3% in the AG groups. The rate of infarctions (therefore the volume of infarct) in the HBO, HBO + AG, and AG groups were found to be significantly decreased compared with the control group (p=0.002, p=0.001, and p=0.001). CONCLUSION: In permanent MCAO-induced ischemia in rats, HBO and AG were observed to have a lowering effect on the infarct volume, but no additive effect was observed. This situation can be explained by different mechanisms of action.