Effects Of Hypobaric Hypoxia On Respiratory And Motor Function In Spinal Cord Injury Rats

Objective: To investigate the effect of the respiratory and motor function of C5 spinal cord injury rats by simulating the environment of low pressure and low oxygen in air transport.Methods: 20 rats were randomly divided into 3 groups,4 rats were divided into group sham operation + normal pressure(SO+NP),8 rats into group spinal cord injury + normal pressure(SCI+NP),8 rats into group spinal cord injury + low pressure(SCI+LP).Rats(group SCI+NP and SCI+LP)were made into spinal cord injury model by compression method.Rats in the three groups were treated with carotid artery catheterization,and were fed for 24 hours.Rats,group SCI+LP,were put into low pressure environment(2500m)for 4 hours.Arterial blood gas,blood routine test,HE staining of spinal cord and lung tissue were detected to evaluate respiratory function,and BBB score was used to evaluate motor function of all rats.Results: 1)Arterial Blood Gas: The partial pressure of carbon dioxide in group SCI+NP was higher than that in group SO+NP(36.50 ± 2.33 vs 33.50 ± 1.29,P = 0.04).There was no significant difference between group SO+NP and SCI+NP in p H,partial pressure of oxygen,oxygen saturation,glucose,lactate,base excess,buffer base and other indicators(P > 0.05).There was no significant difference between group SCI+NP and group SCI+LP in the above indicators(P > 0.05).2)Blood Bell Count: There was no statistical difference between 3 groups,such as leukocyte count,neutrophil percentage,lymphocyte percentage,monocyte percentage,RBC count,hemoglobin content,hematocrit and other indicators(P > 0.05).3)HE staining: In the sham operation group,there was no obvious hemorrhage and exudative change in the HE staining picture of spinal cord,and the tissue structure was complete.HE staining pictures of SCI+NP and SCI+LP showed obvious bleeding,exudation and edema changes.There was significant difference between the tissue structure integrity and SO+NP group,but there was no significant difference between SCI+NP and SCI+LP groups.In the three groups,the alveolar structure was intact without collapse,no obvious hemorrhage was found in the alveoli,and no obvious edema and inflammatory infiltration was found in the interstitium.4)BBB score: there was no significant difference between group SCI+NP and SCI+LP(P>0.05).Conclusion: the respiratory and motor function of C5 spinal cord injury rats was not significantly affected by 4 hours of low pressure and hypoxia,but the longer transport time or different transport waiting time,other spinal cord segments or multi-segments injury need further animal experiments and clinical medical records to verify.