Objective: To study the distribution of collagen X in the intervertebral disc and determine its role in the pathogeny of idiopathic scoliosis (IS).
Methods: The data included apical disc and intermediate disc from 14 cases of AIS, 26 discs from 13 cases of scoliosis of confirmed pathogeny which included 10 cases of congenital scoliosis and neurofibromatosis scoliosis (CS group). Six discs were obtained from 3 cases of sudden death of normal young man served as controls. The distribution of collagen X in the apical disc of IS was examined by immunohistochemistry and in situ hybridization (ISH) with RNA probe. The figure of collagen X hybridization in the endplate cartilage was input to the figure analysis system. The mRNA content of collagen X was compared between every 2 groups by SPSS software.
Results: Collagen X was mainly distributed around the hypertrophic chondrocyte in the endplate cartilage. Its mRNA was expressed in the hypertrophic chondrocyte. Positive signal was found in the nuclei of several scoliosis patients, which was not related to the pathogeny. The collagen X mRNA contents of the apical disc and intermediated disc of the IS group and of the CS group were significantly higher than those of the normal group (P < 0.05). There was no difference between the IS and CS groups.
Conclusions: Collagen X is mainly distributed around the hypertrophic chondrocyte in the endplate cartilage. Its can also be secreted by the chondrocyte-like cells in the nucleus under special condition. Higher expression of collagn X gene in scoliosis patients may be the effects of long term abnormal stress which causes calcification of endplate cartilage. Collagen X expressed in the nucleus may be the result of secretion of chondrocyte-like cells in the disc under abnormal mechanical condition.