Expression Of CaM,β₂M And HSP90 In The Osteoblast Of Adolescent Idiopathic Scoliosis

BackgroundAdolescent idiopathic scoliosis (AIS) is a three dimensional deformity of the spine which occurs during the puberty. lt is one of the focuses of spine surgery due to its serious impairments to growth and mentality of the young patients. Since its etiology is still not clear, AIS is indeed a difficult problem for spine surgeon. Despite extensive research, relatively little is known about the etiology of AIS. Multiple theories have been proposed, and its etiology is probably multifactorial in nature. Some researchers in Peking Union Medical Collage Hospital have constructed subtractive cDNA library from the bone of the AIS patient with suppression subtractive hybridization (SSH) technique. Calmodulin (CAM) gene, heat shock protein 90 gene,β₂ microglobulin (β₂M) gene and heat shock protein 90(HSPg0) gene were identified as the differentially expressed genes in this cDNA library. Therefore, these genes may play an important role in the pathogenesis and progression orAlS and need further study.ObjectiveTo explore the etiology of AIS by studying the expression of Calmodulin (CAM) gene, heat shock protein 90 (HSP90) gene andβ₂ microglobulin (β₂M) gene in the osteoblast of AIS patients.MethodsThe patients were grouped into AIS group and congenital scoliosis (CS) group. The spinal facets of AIS patients and CS patients were obtained and osteoblast was cultured. The condition of the cultured osteoblasts was observed and the expression of CaM,β₂M and HSP90 in those cells were studied by RT-PCR and western blotting method. The results were analyzed by semiquatitative method. The spinal facets of AIS patients and CS patients were also collected and the techniques of HE staining, immunohistochemistry and in situ hybridization were adopted. We studied the pathological changes of the spinal facets of these patients and the distribution of CaM,β₂M and HSP90 in the spinal facets. The images of immunohistochemistry and in situ hybridization were input to the image analysis system and were analyzed semi-quantitatively. The SPSS software was adopted and p<0.05 is defined as the significance level. Results1,The morphology of cultured osteoblasts were observed the same as the documented manifestation and the ALP and VON KOSSA staining are both positive.2,The apical facets of AIS show some signs of regression. The concave apical facets of AIS have thicker cortex but lower porosity than did the convex facets3,There is no different at the ALP activity between the concave side and convex side of apical vertebrae in AIS and CS group, but the ALP activity in CS group is higher than that in AIS group.4,The expression of calmodulin and heat shock protein 90 between the concave side and convex side of apical vertebrae in AIS and CS group have no significant difference. But the expression of calmodulin and heat shock protein 90 in CS group is higher than AIS group with statistical significance except for heat shock protein 90 in the immunohistochemistry result.5,In the osteoblast there is no different the expression ofβ₂M mRNA between the concave side and convex side of apical vertebrae in AIS and CS group, but the expressionβ₂M of in CS group is higher than AIS group with statistical significance. There is no different ofβ₂M in the result of the western blotting. The expression ofβ₂M at the convex side of the apical vertebrae of AIS patients is significantly lower than that of the concave side in the results of the immunohistochemistry and in situ hybridization. In the apical vertebrae of CS patients, there is no difference between the expression at the concave side and that at the convex side in the result of the immunohistochemistry and in situ hybridization. There is no difference in the expression ofβ₂M between AIS and CS patients..CONCLUSION1,The ALP activity in the osteoblast of AIS patients decrease and it maybe relate to the the pathogenesis and progression of AIS.2,The apical facets show some signs of regression. The concave apical facets of AIS have thicker cortex but lower porosity than did the convex facets.3,The low expressions of calmodulin and heat shock protein 90 in the articular process of AIS patients suggest us that these two proteins and articular process play some role in the development and progression of AIS.4,The expression ofβ₂M at the convex side of the apical vertebrae of AIS patients is significantly lower than that of the concave side. It may be the result of reconstrution of bone in the facets following the abnormal mechanical effects. There is some important relationship betweenβ₂M and the reconstrution of bone.β₂M appeared to be an predictor of progression of the AIS.