Expression And Significance Of Ski In Human Intervertebral Disc With Different Degrees Of Degeneration

Objective: Ski is a transforming protein identified as avian Sloan-Kettering virus and is an evolutionarily conserved protein.In osteoarthritis,Ski and its homolog Snon can participate in the suppression of BMP signaling through the negative feedback mechanism that mediates TGF-? induction,and further inhibit the hypertrophy and maturation of chondrocytes.In cardiomyocytes,Ski can regulate the degradation of myocardial extracellular matrix by positively regulating the expression of MMP-9.At the same time,the TGF-? and BMP signaling pathways are closely related to the differentiation,proliferation,apoptosis and extracellular matrix degradation of nucleus pulposus cells in the process of disc degeneration.As the main co-repressor of TGF-? and BMP signaling pathway,the localization distribution and role of disc in the process of disc degeneration are still unclear.Therefore,it is necessary to confirm the expression and function of Ski in the process of disc degeneration.In this study,immunohistochemical staining and Western Blot were used to detect the expressions of Ski and MMP-9 in lumbar intervertebral disc nucleus pulposus tissues with different degrees of degeneration in humans.Expression and significance of Ski in degenerative intervertebral disc.Methods: Thirty patients with lumbar intervertebral discs who underwent surgery at Lanzhou University Second Hospital for lumbar spondylolisthesis,Lumbar spinal stenosis and lumbar disc herniation were collected from January 2019 to March 2019.Statistical analysis was performed on the basic information of patients before surgery.Divided into Pfirrmann ?,Pfirrmann ?,Pfirrmann ? 3 groups according to the Pfirrmann classification standard,HE staining was used to observe the morphology of lumbar disc tissue with different degrees of degeneration.Immunohistochemical staining was used to detect the expression of Ski and MMP-9 in lumbar disc tissue.Western Blot detection Expression of Ski and MMP-9 in lumbar disc tissue.Human nucleus pulposus cells were cultured,and the expression localization of Ski in human nucleus pulposus cells was detected by immunofluorescence.Results: Except for age(P<0.05),gender,smoking,and heavy labor factors were not statistically different between the groups before surgery.The pathological staining of HE showed that collagen fibers in Pfirrmann type ? intervertebral disc tissue were arranged neatly,small vacuole cells were arranged uniformly,and cell clusters appeared less;Pfirrmann ? and Pfirrmann ? type collagen fibers were obviously irregularly arranged,and cells showed large vacuoles.Shaped and uneven,with more cell clusters.At the same time,the histology score is consistent with the Pfirrmann rating(P<0.05).Immunohistochemical staining showed that Ski and MMP-9 were mainly expressed in intervertebral disc nucleus pulposus cells in Pfirrmann ?,Pfirrmann ?,and Pfirrmann ? groups,and they showed a significant increasing trend(P<0.05).Western Blot tests showed that the expression levels of Ski and MMP-9 in the Pfirrmann ?,Pfirrmann ?,and Pfirrmann ? groups all showed increasing trends to varying degrees(P<0.05).Nucleus pulposus cells immunofluorescence showed that Ski was mainly expressed in the nucleus of nucleus pulposus cells.Conclusion: It was firstly confirmed that Ski was expressed in the nucleus pulposus of the intervertebral disc,and the expression gradually increased with the increase of the degree of degeneration,which was positively correlated with the degree of disc degeneration.At the same time,the expression of Ski and MMP-9 also showed a certain positive correlation,and they may participate in the process of intervertebral disc degeneration.At the same time,this study firstly confirmed that Ski was mainly expressed in human nucleus pulposus cells in intervertebral disc tissue.