The Correlation Between Spatiotemporal Expression Of Tubulin,Aquaporin-4,K+Channel 4.1 And Spinal Cord Edema After Spinal Cord Injury

OBJECTIVE: To investigate the temporal changes of tubulin,aquaporins-4 and K+Ion Channel Protein-4.1 after acute spinal cord injury in rats by making acute spinal cord injury(ASCI)in rats.And explore the relationship between these three and the development of spinal cord edema after acute spinal cord injury,and explore its mechanism.METHODS: Ninety adult female Sprague-Dawley rats were randomly assigned to a sham operation group(n=30)and an injury group(n=60).The sham operation group was a blank control group(30 rats)and the 10 th thoracic vertebra was located(T10).After the lamina was exposed,the T10 lamina was bitten and sutured layer by layer.The injury group was ASCI group(60 rats),with five time points of 6h,1d,3d,5d and 7d,and 12 rats in each subgroup.The T10 strike damage model was prepared by the Allen strike method with a strike strength of 20 g x 2.5.Spinal water content was measured at 6h,1d,3d,5d and 7d after injury.HE staining was performed on the spinal cord of each group at 6h,1d,3d,5d and 7d after operation to observe the spinal cord after acute spinal cord injury.Pathological changes.The spinal cord tissues of each injury group were treated with tubulin,aquaporin 4 and potassium channel 4.1 immunohistochemical staining and Western-blotting at each time point to observe the expression changes and relative gray scale of the three histone proteins after acute spinal cord injury.Value analysis.Correlation analysis was performed on the changes of three groups of protein expression and the changes ofwater content in spinal cord edema at each time point in each subgroup of the injury group.RESULTS: There was no significant difference in the water content of the spinal cord before operation(P>0.05).The water content of the spinal cord increased at 6h after injury and reached the peak on the 5th day.HE staining showed: sham operation group The spinal cord tissue was intact,the intramedullary tissue was evenly distributed,the white matter and gray matter structure were clear and intact,and the cells were arranged in an orderly manner.At 6 hours after injury,mainly gray matter and central tube hemorrhage were observed,and the cell gap showed swelling;1 day after injury,the gray matter of the spinal cord was severely hemorrhagic.Structural disorder,neuronal swelling;3d after injury,gray matter white matter necrosis area increased,cell swelling was obvious,neuron nucleus condensed,5d and 7d after injury,cerebral gray matter hemorrhage decreased,necrosis was serious,cell edema was obvious,The cystic cavity and vacuoles are formed and the number of neurons is reduced.Immunohistochemical and semi-quantitative analysis showed that AQP4 was expressed in the normal spinal cord,mainly distributed in the central tube and gray matter.The expression decreased slightly at 6h after injury,increased after 1d,and increased significantly at3 d after injury.At the peak,it decreased slightly at 7d,while tubulin expressed the same trend as potassium channel 4.1.The expression level in sham operation group was higher than that in subgroup at each time point,that is,the expression level decreased slightly at 6h and 1d after operation,3d The decrease was obvious and the lowest on the 5th day after injury,and the expression on 7d increased again.Western-blot analysis showed that the results of AQP4,tubulin and kir4.1 relative gray value analysis were basically consistent with the percentage analysis of immunohistochemical positive cells,that is,the expression of AQP4 increased gradually with the change of spinal cord injury,and the highest after the 5th day.On the 7th day,microtubules and Kir4.1 were opposite to AQP4 expression,that is,the expression gradually decreased after injury,and peaked on the 5th day,and slightly increased on the 7th day.AQP4 expression was positively correlated with spinal cord water content after injury,while tubulin and Kir4.1 were negatively correlated with spinal cord water content.Conclusion: This study is the first to identify the distribution of AQP4,tubulinand Kir4.1 in the spinal cord and the expression changes after injury in acute spinal cord injury,and found that AQP4 expression increased and tubulin,Kir4.1 decreased and injured Changes in water content in the posterior spinal cord are correlated and may lead to the formation of spinal edema.