Neuroprotective effect of co-administered vitamin E isoforms on crush-injured sciatic nerve of diabetic rats

Abstract

Diabetic peripheral neuropathy is believed to be due to vascular deficit, altered antioxidant defense mechanism and glycemic status. This study is designed to explore the effect of co-administration of some natural antioxidants e.g. vitamin E isoforms, on the regeneration of crush-injured sciatic nerve in healthy and diabetic rats. Diabetes was induced through single subcutaneous injection of alloxan at the dose of 100 mg/kg. Twenty four albino rats were divided into four groups; healthy control, diabetic control, healthy treated and diabetic treated. Treated groups received 100 mg/kg of d-α-tocopherol and d-δ-TRF each, orally and daily for three weeks. A horizontal skin incision was made on shaved right mid-thigh region and sciatic nerve was approached by splitting and retraction of surrounding muscles followed by the crushing of sciatic nerve proximal to its division with Kocher’s forceps. Skin wound was closed with an absorbable suture. Sciatic functional and static indices were used to assess the functional recovery. The histopathology, histomorphology of crushed nerve and serum biochemical study were performed at the end of third week. One-way ANOVA followed by Tukey’s test and Student’s t test were used for statistical analysis of data. All results revealed that vitamin E isoforms on co-administration synergistically improve the antioxidant status, glycemic level; promote neovascularization, regeneration and remyelination of nerve fibers and matrix remodeling after crushed injuries of sciatic nerve. It is concluded that these vitamin E isoforms are potent therapeutic dietary supplements on peripheral nerve regeneration in both healthy and diabetics.