TGF-β增强rhBMP-2诱导成骨中Ⅰ,Ⅱ型胶原及碱性磷酸酶的表达

Expression of collagen Ⅰ, Ⅱ and alkaline phosphatase in osteogenesis induced by rhBMP-2 enhanced by TGF-β

目的 对β转化生长因子 (TGF β)增强人重组骨形态发生蛋白 2 (rhBMP 2 )诱导成骨中CollagenⅠ ,Ⅱ及碱性磷酸酶 (ALP)的表达进行研究 .方法 BALB/c小鼠 110只随机分为 2组 ,每组 5 5只 ,设立rhBMP 2 /TGF β为实验组 ,rhBMP 2为对照组 ,分别于 3～ 2 1d共 8个时间点取材 ,采用免疫组织化学方法对新生骨组织中的Ⅰ ,Ⅱ型胶原进行检测 ;对ALP活性进行定量分析 ,观察 2组在诱导成骨中CollagenⅠ ,Ⅱ及ALP的表达情况 .结果 Ⅱ型胶原的出现是和成软骨、软骨细胞的出现相伴随的 ,但是 ,肥大、变性的软骨细胞并不表达Ⅱ型胶原 .作为成骨细胞成熟标志物的Ⅰ型胶原、ALP在软骨形成期即有表达 ,但是随着成骨细胞的出现 ,骨组织的形成Ⅰ型胶原仍表现为高表达 ,而ALP的表达则呈下降趋势 .实验组CollagenⅠ ,Ⅱ及ALP的表达早于对照组 .结论 TGF β增强了rhBMP 2诱导成骨中CollagenⅠ ,Ⅱ及ALP的表达 .

AIM To study the expression of collagen Ⅰ, Ⅱ and alkaline phosphatase in osteogenesis induced by rhBMP 2 enhanced by TGF β. METHODS 110 BALB/c mice were divided into two groups at random, 55 in each group. Mice receiving rhBMP 2/TGF β served as the experimental and those receiving rhBMP 2 served as the control. In order to investigate the expression of collagen Ⅰ, Ⅱ and alkaline phosphatase in osteogenesis induced by rhBMP 2/TGF β and rhBMP 2, immunohistochemistry analysis was performed 3, 5, 7, 9, 11, 14, 17 and 21 days after the implantation. Meanwhile, alkaline phosphatase activity was measured 7, 14 and 21 days after the implantation. RESULTS The appearance of type Ⅱ collagen was accompanied by that of chondroblasts and chondrocytes, but hypertrophic and degenerative chondrocytes could not express type Ⅱ collagen. Type Ⅰ collagen and ALP, osteoblast differentiation markers, were expressed at the early stage of chondrogenesis. However, with the appearance of osteoblasts and osteogenesis, type I collagen was still expressed at higher level but ALP decreased gradually. Expression of collagen Ⅰ, Ⅱ and alkaline phosphatase in the experimental was prior to that in the control. CONCLUSION TGF β enhances the expression of collagen Ⅰ, Ⅱ and alkaline phosphatase in osteogenesis induced by rhBMP 2.