Effects of hypobaric hypoxia on respiratory and motor function in spinal cord injury rats / 解放军医学杂志

ABSTRACT

Objective To investigate the effect of hypobaric hypoxia on the respiratory function of C5 spinal cord injury rats by simulating the environment of low pressure and low oxygen in air transport. Methods 20 male SD rats were randomly divided into 3 groups sham operation group (n=4), spinal cord injury group (n=8) and spinal cord injury + low pressure group (n=8). Spinal cord injury model was made by compression method. These rats in the three groups were treated with carotid artery catheterization, and were fed for 24 hours. Spinal cord injury + low pressure group was put into 2500 m low pressure environment for 4 hours. Arterial blood gas, blood routine test, HE staining of the spinal cord and lung tissue were detected to evaluate respiratory function, and BBB score was used to evaluate motor function of rats. Results There was no significant difference between the three groups in pH, oxygen partial pressure, carbon dioxide partial pressure, oxygen saturation, glucose, lactate, alkali surplus, buffer alkali and other indicators (P>0.05). The percentage of reticulocyte in spinal cord injury group was lower than that in sham operation group (2.05%±0.69% vs. 2.88%±0.20%, P=0.034), there was no significant difference between spinal cord injury + low pressure group and other two groups (2.37%±0.59% vs. 2.88%±0.20%, P=0.178; 2.37%±0.59% vs. 2.05%±0.69%, P=0.282). There was no significant difference among the three groups in the leukocyte counts and percentage of neutrophils, lymphocytes, monocytes, erythrocytes, hemoglobin and hematocrit (P>0.05). HE staining showed that there was no obvious bleeding and exudative changes in spinal cord in sham operation group, and the tissue structure was intact. The histological integrity of spinal cord injury group and spinal cord injury + low pressure group was significantly different from that of sham operation group, but there was no significant difference between the two groups. There was no significant difference in bleeding, exudation and edema between the three groups, and the alveolar structure was intact. BBB score showed no significant difference between spinal cord injury group and spinal cord injury + low pressure group (P=0.440). Conclusion The respiratory and motor function of C5 spinal cord injury rats would not be significantly affected by 4 hours of low pressure and hypoxia.