Effect Of Insulin-like Growth Factor-1, Platelet-derived Growth Factor And Transforming Growth Factor-β₁ On The Biological Potential Of The Human Degenerative Annulus Fibrosus Cells

Objective:The cell matrix of intervertebral disc includes collagen and proteoglycan. The intervertebral disc degeneration is displayed by the changes of the cell proliferation and the cell matrix's metabolism. The growth factors have effect on the cell differentiation. proliferation and matrix's metabolism, are used to biological repair degenerative intervertebral disc. Nowadays, the study concerning the effect of growth factors on annulus fibrosis is scanty.This research studies the effects of insulin- like growth factor- 1 ( IGF-1),platelet-derived growth factor ( PDGF),transforming growth factor-β1 ( TGF-β1) on the biological potential of the human degenerative annulus fibrosus (AF) cells in vitro, as to expand the study on growth factors to treat the human intervertebral disc degeneration.Method:Primary cells of human degenerative AF were obtained through in vitro monolayer culture combined with enzyme digestion method and tissue pieces culture method. After passage, cells were identified through immunohistochemical staining. The cells of passage 3 were treated separately with different growth factors.They were divided into 8 groups: IGF- 1 group,PDGF group,TGF-β1 group,IGF-1+ PDGF group,IGF-1+TGF-β1 group,PDGF+TGF-β1 group,IGF-1 + PDGF + TGF-β1 group and the control group . On the third and the sixth day after growth factors treatment , the cell proliferation was detected by MTT assay; the contents of collagen typeⅠ,Ⅱand Aggrecan on the cell supernatants were detected by enzyme-linked immunosorbent assay(ELISA).The optical density (OD) volume was converted to density volume by using Curve Expert1.3 soft, and the data was analysed by SPSS 13.0 soft.Results:Collagens typeⅠand typeⅡimmunohistochemical staining of passage 3 cells were positive. IGF-I had the effects of stimulating the cell proliferation, slightly inhibiting the synthesis of collagen typeⅠ, stimulating the synthesis of collagen typeⅡand aggrecan , slightly stimulating more synthesis of collagen typeⅡthan TGF-β1. PDGF could stimulate more cell proliferation than IGF-Ⅰ, inhibited the synthesis of collagen typeⅠand slightly stimulated the synthesis of collagen typeⅡ. But it contributed nothing to the synthesis of aggrecan. TGF-β1 inhibited the cell proliferation and stimulated the synthesis of collagen typeⅠ, typeⅡas well as aggrecan. Its ability of stimulating aggrecan synthesis was greater than that of IGF-Ⅰ. No synergistic effect presented in the groups with factors alliance, which accordingly had no advantage over the groups with single factor.Conclusion:TGF-β1,IGF-I and PDGF can greatly effect the biological potential of the human degenerative annulus fibrosus cells.The three growth factors can be used in the biological treatment on the human intervertebral disc degeneration.