The expression of collagen IX in the apical disc of idiopathic scoliosis

Objective To study the distribution of collagen Ⅸ gene in the disc and to determine its role in the pathogeny of idiopathic scoliosis (IS). Methods The data included apical disc and intermediate disc from 14 cases of adolescent IS, 26 discs from 13 cases of scoliosis of confirmed pathogeny(CPS), which included 10 cases of congenital scoliosis and neurofibromatosis scoliosis. Six discs were obtained from 3 cases of normal young man served as controls. The distribution of collagen Ⅸ was studied in the apical disc of IS by immunohistochemistry and in situ hybridization (ISH) with RNA probe. The figure of collagen Ⅸ hybridization in the endplate cartilage was input to the figure analysis system. The mRNA content of collagen Ⅸ was compared between each group by SPSS software. Results Collagen Ⅸ was mainly distributed in the inner fibrous annulus, nucleus and endplate cartilage. Collagen Ⅸ was secreted by the little round chondrocyte-like cells,which was not expressed in the hypertrophic cells. There was significant difference of collagen Ⅸ mRNA content between the concave side of apical disc in the IS and the normal disc(P0.05),and also between intermediate vertebrae of CS group and normal. Conclusions There is no obvious abnormal distribution of collagen IX in the disc of idiopathic scoliosis. Collagen IX may be related to the pathogensis of IS. More investigation such as quantity analysis and protein function determination is needed to confirm its role in the pathogensis of IS.