Study Of The Hemodynamics, Blood Vessel Wall And Pathophysiological Changes As It Relates To Limb Ischemic Reperfusion Injury After Low Abdominal Aortas Blockage Of The Rabbits

Objective:To study the hemodynamics,blood vessel wall and pathophysiological changes as it relates to limb ischemic reperfusion injury and the survival of animals after low abdominal aortas blockage.Method:The model was establishedby clamping rabbit's abdominal aortas for 1 hour and 1.5 hours,then samples of blood(MAD and SOD) were collected.Quadriceps femoris,gastrocnemiusand blocked blood vessel wall changes under light microscope were examined before blood blockage and at different time points during reperfusion.Measure heart rate,blood pressure changes before and after blockage treatment were done,and the survival condition in the following week was observed.Result:Compared with the control group,the increase of blood MAD and the decrease of SOD were not obvious(P＞0.05)in 1 hour block group(B1).Under the light microscope quadriceps femoris Changes were not obvious,gastrocnemius cells appeared slight swollen,but recovered mostly after one week.After artery blockage,the blood pressure increased,heart rates slowed,and when blockage was stopped blood the pressure dropped and heart rate increased(P＜0.05).Two hours after reperfusion,in the blood vessel wall,the endodermis,was partly necrosed,but the inner elastic membranes basically maintained its integrity under light microscope.After one week,the endodermis cells were partly necrosis,shedding and accrementition were in concomitance,inflammatory cells infiltrated in the interstitial substance of the vascular smooth muscle cells,the blood vessel wall layer structure was distinct.In the 1.5 hours blockage group(B2), blood MDA increased and SOD decreased(P＜0.05)when reperfused. Quadriceps femoris and gastrocnemius muscle cells appeared different degree of edema,but cell necrosis was not obvious.Oedema was more severe in the gastrocnemius muscle than in the quadriceps femoris. After one week the muscle cell nucleus enlarged and there was interstitial cell hyperplasia The interstitium tended to fibrosis, which indicated that muscle cell function was incapacitated.After blockage,the blood pressure increased,the heart rates slowed,and when the blockage was removed,the blood pressure dropped,the heart rates turned rapid(P＜0.05).Two hours after reperfusion the blood vessel wall changed,the endodermis disappeared,part of inner elastic membranes collapsed.One week later,the blood vessel wall layer structure disappeared and there were large areas of necrosis,the lumens were obstructed by necrosis and shedding tissue,the inner elastic membranes disappeared.In experiment B3,all(8)rabbits survived healthily,the assessment of posterior limbs neuro-function after treatmen were grade 5.In experiment B4,five(5)rabbits survived, the assessment of posterior limbs neuro-function after treatmen were grade 3-4.Conclusion The blockage of rabbits abdominal aortas for 1 hour produced slight pathological change,there were no effect on survival and posterior limbs function.While 1.5 hours blockage produced serious pathological change,affecting the survival and posterior limbs function.The blockage of rabbit abdominal aortas should control to within 1 hour.