骨形态发生蛋白诱导成骨过程中转化生长因子β1的mRNA表达

mRNA expression of transforming growth factor β1 in inducing osteogenesis of bone morphogenetic protein

目的 通过观察骨形态发生蛋白 (bonemorphogeneticprotein ,BMP)诱导成骨过程中转化生长因子 β1(transforminggrowthfactorβ1,TGF - β1)的基因表达情况 ,探讨诱导成骨过程中是否有其他生长因子参与 ,进一步阐明BMP诱导成骨的机制。 方法 采用日本大耳白兔 16只 ,手术造成左尺骨中上段 12mm骨缺损实验模型 ,随机分为实验组及对照组 ,实验组缺损内植入以牛松质骨基质颗粒 (经脱钙、脱蛋白及高温、高压处理 )为载体的牛骨形态发生蛋白 (bBMP) 10mg ;对照组缺损内仅植入牛松质骨载体。分别于术后第 3,7,14,2 1天取两组缺损内组织冰冻切片 ,采用原位杂交方法 ,检测组织中TGF - β1的mRNA表达并作图像分析。 结果 实验组和对照组早期各时相均有TGF - β1的mRNA表达 ,表达细胞主要为间充质细胞、软骨细胞和成骨细胞 ,表现为在这些细胞胞浆内出现紫蓝色颗粒 ,颗粒的大小及颜色的深浅表示基因表达信号的强弱。实验组TGF -β1的mRNA表达在术后第 14天达高峰 ,此时正为软骨细胞和成骨细胞大量形成期 ;对照组各时相TGF - β1的mRNA表达信号均明显弱于同期实验组。图像分析结果采用方差分析 ,显示两组间差异有显著性意义。 结论 TGF - β1的mRNA表达在BMP诱导成骨中明显增强 ,BMP具有促进TGF - β1合成及?

Objective Through observing the mRNA expression of tran sforming growth factor β1 (TGF-β1) in the course of bone morphogenetic protei n (BMP) inducing osteogenesis, to investigate whether some other growth factors h ave taken part in the courses of inducing osteogenesis of BMP, so to expound the inducing mechanism of BMP. Methods An experimental model of 12 mm bone defect in the lef t ulna of 16 rabbits was adopted. These rabbits were divided into experimental g r oup and control group at random. Specially treated bovine cancellous was adopted a s a carrier of BMP. BMP 10 mg/carrier and carrier only were implanted into the b o ne defect area of experimental group and control group, respectively. Tissues in the bo ne defect area was extracted from both the experimental and control groups on th e 3rd,7th,14th, and 21st day, respectively. An in situ hybridization method was used to detect the mRNA expression of TGF-β1, and to analyze the mRNA expr ession using image analysis. Results TGF-β1 mRNA expression was seen in both experime ntal and control group at the early stage after implantation. The peak mRNA expr ession of TGF-β1 of the experimental group appeared on the 14th day, accompan ied by numerous chondrocytes and osteoblasts. Image analysis found that the TGF -β1 mRNA expression was significantly higher in experimental group than in control group at same time phases. Conclusions The mRNA expression of TGF-β1 is found in the c ourse of BMP inducing osteogenesis. BMP has the effect of promoting the formatio n and secretion of TGF-β1. TGF-β1 and some other growth factors may be neede d in inducing osteogenesis of BMP.