药物容量对局部灌注药物保护缺血脊髓模型的影响

Effects of drug volume on the model for regional drug protection against spinal cord ischemiareperfusion injury in rabbits

目的比较腹主动脉不同药物灌注容量对兔局部灌注药物保护缺血脊髓模型的影响。方法采用。肾下腹主动脉阻断法建立兔脊髓缺血再灌注损伤模型，缺血期间，V1．5、V3和V6组分别向阻断的腹主动脉段内灌注生理盐水1．5、3．0或6．0mL/kg，V0组仅阻断不灌药。比较各组阻断部位远端腹主动脉平均压（MAP）、后肢运动功能及脊髓病理学变化。结果V6、V3、V1．5和V0组缺血期间MAP分别为（49．4±4．5）、（41．0±5．5）、（22．5±1．7）和（17．9±2．6）mmHg（1mmHg=0．133kPa），V6和V3组显著高于V0组（P〈0．05）；缺血期间与再灌注初期10minMAP的差值分别为（32．3±9．4）、（44．9±8．9）、（61．8±4．5）和（62．5±6．3）mmHg，V6和V3组显著低于V0组（P〈0．05）。V6组所有时点神经行为学评分和再灌注48h脊髓前角正常运动神经元计数[10（5．0～12．0）个]均显著高于VO组[0（0～4．5）个]（P〈0．05）；其余各组与V0组差异无统计学意义（P〉0．05）。结论缺血期间以3．0mL/kg及以下容量向阻断的腹主动脉段内灌注药物，可保证脊髓损伤模型的稳定性，尤以1．5mL/kg最为可靠。

Objective To compare the effects of different drug volume on the model for regional aorta-infused drug protection against spinal cord ischemia-repeffusion injury in rabbits. Methods Spinal cord ischemia model was induced in New Zealand white rabbits by infrarenal abdominal aorta occlusion with a balloon catheter for 30 rain. Another polycarbonate catheter was inserted into the abdominal aorta with the tip close to the site of occlusion via the femoral artery. During the ischemic period, nothing （V0 group） or different volume （1.5, 3.0 or 6. 0 ml/kg） of normal saline containing methylene blue （V1.5, V3 and V6 groups） was consecutively infused into the occluded aortic segments via the polycarbonate catheter at differ- ent rate of 3.0, 6. 0, or 12.0 ml/（ kg.h）. The bilateral common iliae arteries were clamped simuhaneouly to prevent drug solution leakage. Thirty min later, blood flow was regained for reperfusion. The change of mean aortic pressure distal to the occluded site was measured throughout the operation. Neurological func tion was assessed according to the modified Tadov scales at the moment of palinesthesia and 6, 24 and 48 h after repeffusion. Lumbar segements of the spinal cord （ L4-5 ） were harvested at 48 h after repeffusion for histopathologic evaluation, and the total number of normal motor neurons in the anterior horn was counted. Results The abdominal aorta was not completely occluded in V6 group. In V3 and V6 groups, the distal aortic pressure during ischemia was higher than in V0 and V1.5 groups with （41.0 ±5.5） and （49.4 ± 4.5） vs. （17.9±2.6） and （22.5 ±1.7） mmHg [1 mmHg=0.133 kPa, P〈0.05], while the differ ence value between ischemia and the first 10 rain of reperfusion was lower than in V0 and V1.5 groups with （44. 9 ±8.9 ）and （32.3±9.4） vs. （62. 5 ±6. 3） and （61.8 ±4. 5） mmHg （P 〈0. 05）. Tarlov scores were higher in V6 group than in V0 group at all intervals （ P 〈 0. 05 ）. The number of normal motor neurons was greater in V6 group than in V0 group with 10 （5.0-12. 0） vs. 0 （0-4. 5） （P 〈0. 05）. There was no significant difference between other groups and V0 group （ P 〉 0. 05 ）. Conclusion Drug volume lower than 3 ml/kg can ensure the model stability of spinal cm＇d injury when infused into the occluded aortic seg ments during the isehemic period. The optimal volume was 1.5 mL/kg.