Abstract: Objective To observe the effect of pretreatment of aprotinin on nitric oxide (NO) and nitric oxide synthase (NOS) contents after ischemia-reperfusion injury of spinal cord in rabbits.Methods 45 rabbits were randomly divided into aprotinin treatment group (group A), normal saline control group (group B) and pseudo-surgical operation group (group C) with 15 rabbits in each group. The infrarenal segment in abdominal aorta was clamped for 60 min to construct the model of lumbosacral spinal cord ischemia in rabbits. Reperfusion was followed and kept on for 24 h until the blood flow regained normal. Aprotinin was given 3×10⁷ IU/kg as a short time intravenous injection for 10 min before ischemia, and then was drilled with micro pump by 1×10⁷ IU/kg/h. Normal saline was used in group B, the ischemia-reperfusion duration between group A and group B remained same. The group C was only exposured abdominal aorta and not clamped. The rabbits were killed before ischemia and at 8 h, 24 h after ischemia-reperfusion, lumbar segment spinal cords were harvested to detect contents of NO and NOS of spinal cord.Results After 8 h of ischemia-reperfusion,the contents of NO, total NOS (TNOS), and induced NOS (iNOS) in group A and group B were more than that before ischemia (P＜0.05). After 8 h of ischemia-reperfusion, there was a significant difference in the contents of NO, TNOS, iNOS between group A and group B (P＜0.05～0.01). After 24 h of ischemia-reperfusion, there was a significant difference too between group A and group B (P＜0.01). After 8 h and 24 h ischemia-reperfusion, the contents of NO, TNOS, iNOS in group A and group B were more than that in group C (P＜0.01).Conclusion During the ischemia-reperfusion, more NO produced is an important factor of spinal cord injury. Aprotinin can decrease the contents of NO and ischemia-reperfusion injury to spinal cord of rabbits.

Key words: aprotinin, spinal cord, ischemia-reperfusion, nitric oxide, nitric oxide synthase