Temporal And Spatial Variation Of SKIP Expression In Injured Spinal Cord Of Rats And Its Effect

Objective The lesions and repair process often accompanied by a series of pathophysiological changes after spinal cord injury,and these pathophysiological were closely related to the changes of some cells and molecules.In this study,by establishing animal model and experimental observation,we investigated the temporal and spatial changes of SKIP(Ski-interacting protein)expression in normal and injured spinal cord of rats,and the role of SKIP in the process of injury and rehabilitation.Methods According to the table of random number,90 adult female Sprague-Dawley rats were randomly split into two groups: sham operation group(n = 45)and spinal cord injury(SCI)group(n = 45),each group had five time points(1 days,3 days,5 days,7 days,14 days),9 rats per time point.The sham group only bit the lamina of rats,and spinal cord injury model at T10 was established with modified Allen's technique(10 g × 25 mm).All rats of two groups were followed by Basso-Beattie-Bresnahan(BBB)scores at each time point to evaluate its behavioral function.Three rats were selected at each time point after the completion of the scoring,and the spinal cord tissue was made into frozen sections and then stained with Nissl staining to observe the pathological changes of spinal cord neurons after injury.The expression of SKIP in normal and injured spinal cord tissue was observed by immunofluorescence staining of the spinal cord tissue of 3 rats at each time point.Western blot was used to detect the expression of target protein(SKIP)in the spinal cord tissue after 3 rats in each group were extracted from each group.Results 1,The BBB scores of each time point in the injury group were lower than those in the sham operation group(n = 9,P <0.01).2,The results of Nissl staining showed that: compared with the sham operation group,Nissl bodies that in the cytoplasm of spinal cord neurons began to disintegrate,coalesce and irregular distribution,the neurons began to degenerate and die at the 5th days;the damage increased at the 14 th day.The expression of SKIP was mainly dispersed in the gray matter of the spinal cord and little expression in the white matter.The expression of SKIP was low expression in normal spinal cord,after injury,SKIP expression gradually increased,reached the peak at 5th day and decreased significantly at 14 th day.The optical density analysis showed that the expression of SKIP was significantly increased compared with sham group(N = 3,P <0.05).The results of double labeling showed that SKIP and neuron-specific marker(NeuN)showed co-expression signal in the spinal cord gray matter after SCI,and showed no co-expression signal with the specific markers of glial fibers(GFAP).Western Blot showed that the expression of target protein(SKIP)increased first and then decreased after spinal cord injury,which was consistent with the results of immunofluorescence.Conclusion This study explored the location of SKIP expression in normal and injured spinal cord tissue and the changes of SKIP expression after spinal cord injury,combined with the pathology of Nissl bodies in spinal neurons and spinal cord neurons,we conclude that SKIP may be a new signaling molecule that expressions in the spinal cord neurons and affects its apoptosis.