Protective Effects of Endothelin Receptor Antagonist on Traumatized Spinal Cord in Rats / 中国矫形外科杂志

ABSTRACT

Objective: To evaluate the effects of PD145065(non-selective endothelin(ET)receptor antagonist)on injured spinal cord and explore mechanisms of how ET plays a role in secondary injury following spinal cord injury(SCI).Methods:Spinal cord of rat was traumatized by compression(50g,1min).PD145065 or vehicle was administered intrathecally 10 minutes before SCI.Alterations of spinal cord blood flow(SCBF),molondialdehyde(MDA),the total content of intracellular calcium(［Ca2+］i),Evans blue(EB),and water in spinal cord were inspected.Results:SCBF of injured area decreased obviously 5 minutes after SCI.SCBF was 75.23±9.21% of baseline 5 minutes after SCI,57.06±7.35% 2 hours.SCBF of adjacent area decreased lower.SCBF was 79.82±7.98% of baseline 30 minutes after SCI.SCBF of injured and adjacent areas did not recover 4 hours after SCI.The contents of MDA,［Ca2+］i,EB and water in traumatized spinal cord were significantly more than that of sham(P＜0.05)。PD145065 ameliorated SCBF of injured area obviously and abolished the decrease of SCBF of adjacent area.The contents of MDA,［Ca2+］i,EB and water in spinal cord of PD145065 treated group were significantly less than that of saline treated group(P＜0.05).Conclusion:PD145065 has protective effects on traumatized spinal cord in early phase.ET and its receptors may play a role in secondary injury following SCI by multiple pathways.ETA/ETB receptor antagonist may be useful in treatment of clinical SCI.