Quantitative analysis of types I and II collagen in the disc annulus in adolescent idiopathic scoliosis

Objective: To find the possible roles of collagen in the pathogenesis of AIS through studies of the distribution of the collagen I and II in the disc annulus fibrous in adolescent idiopathic scoliosis (AIS). Methods: The disc annulus fibrous of apex curve were harvested during anterior surgery and divided into concave and convex samples. 25 AIS cases were covered in this study including 6 males and 19 females, with an average age of 14.6 years (range 12-18 years). 11 specimens were intervertebral disc from the thoracic region (from T8 to T11) and 14 sample were from lumbar discs (from L1 to L2). RT-PCR was employed to investigate the distribution and content of collagen I (220bp) and collagen II (359bp) in the inter-vertebral disc specimens. 1% agarose gel electrophoresis and the Gelwork image analysis system was used in the semi-quantitative analysis of the product. Results : For the AIS group, type I collagen and type II collagen significantly increased on convex side compared with that of the concave side (p < 0.01). The same trend was observed in both thoracic and lumber disc annulus fibrosis, but there was no statistical difference expect for the expression of type II collagen in convex side of disc annulus fibrous (p < 0.05). Conclusion: The asymmetric expression of collagen I and II collagen showing that there was degeneration in the intervertebral disc of AIS. The abnormal collagen metabolism may be one of reasons in the development of AIS and probably an important factor in the progression of AIS.