Changes with Age and the Effect of Recombinant Human BMP-2 on Proteoglycan and Collagen Gene Expression in Rabbit Anulus Fibrosus Cells

In order to compare the difference between young and old intervertebral disc cells and theirresponsiveness to recombinant human bone morphogenetic protein-2 (rhBMP-2),disc cells were isolatedfrom the anulus fibrosus (AF) and transition zones of lumbar discs from eight old and eight young NewZealand white rabbits.Compared with the ceils from the young rabbits,cells from old rabbits respond less torhBMP-2 treatment with respect to sulfated-glycosaminoglycan (sGAG) synthesis and aggrecan geneexpression.But in collagen Ⅰ and collagen Ⅱ gene expressions,there are no significant differences betweenthe old and the young.When comparing sGAG content,aggrecan,and collagen Ⅱ gene expression of the oldAF cells after rhBMP-2 treatment with that of the young AF cells without rhBMP-2 treatment,the old AFcells with rhBMP-2 treatment have a greater capacity to synthesize sGAG bound in the cells and to releasesGAG in the media,as well as to express aggrecan and collagen Ⅱ gene.It can be concluded that old AF cellsafter rhBMP-2 treatment have a greater capacity to synthesize sGAG and express aggrecan and collagen Ⅱ ascompared to young AF cells without rhBMP-2 treatment.Thus rhBMP-2 can reverse the decline in theanabolic capacity of the disc cells with ageing.So it seems that rhBMP-2 has potential for use as an agent toretard a key component of disc degeneration and loss of disc matrix.