A potential protective effect of α-tocopherol on vascular complication in spinal cord reperfusion injury in rats

BACKGROUND: Paraplegia remains a potential complication of spinal cord ischemic reperfusion injury (IRI) in which oxidative stress induced cyclooxygenase activities may contribute to ischemic neuronal damage. Prolonged administration of vitamin E (α-TOL), as a potent biological antioxidant, may have a protective role in this oxidative inflammatory ischemic cascade to reduce the incidence of paraplegia. The present study was designed to evaluate the preventive value of α-TOL in IRI of spinal cord. METHODS: For this study, 50 male Sprague-Dawley rats were used and divided into five experimental groups (n = 10): Control group (C); α-TOL control group (CE) which received intramuscular (i.m.) α-TOL injections (600 mg/kg); Sham operated group (S), IRI rats were subjected to laparotomy and clamping of the aorta just above the bifurcation for 45 min, then the clamp was released for 48 hrs for reperfusion; and IRIE rats group, received 600 mg/kg of α-TOL i.m. twice weekly for 6 weeks, followed by induction of IRI similar to the IRI group. At the end of the experimental protocol; motor, sensory and placing/stepping reflex evaluation was done. Plasma nitrite/nitrate (NOx) was measured. Then animals' spinal cord lumbar segments were harvested and homogenized for measurement of the levels of prostaglandin E(2 )(PGE(2)), malondialdehyde (MDA) and advanced oxidation products (AOPP), while superoxide dismutase (SOD) and catalase (CAT) activity were evaluated. RESULTS: Induction of IRI in rats resulted in significant increases in plasma levels of nitrite/nitrate (p < 0.001) and spinal cord homogenate levels of PGE(2), MDA, advanced oxidation protein products AOPP and SOD with significant reduction (p < 0.001) in CAT homogenate levels. Significant impairment of motor, sensory functions and placing/stepping reflex was observed with IRI induction in the spinal cord (p < 0.001). α-TOL administration in IRIE group significantly improved all the previously measured parameters compared with IRI group. CONCLUSIONS: α-TOL administration significantly prevents the damage caused by spinal cord IRI in rats with subsequent recovery of both motor and sensory functions. Alpha-tocopherol improves the oxidative stress level with subsequent reduction of the incidence of neurological deficits due to spinal cord IRI conditions.