激活素A、TGF-β1在兔下颌骨牵引中的表达

目的 检测下颌骨牵引过程中激活素A(ACT A)及转化生长因子β1(TGF-β1)的表达情况，了解ACTA、TGFβ1在下颌牵引成骨中作用的异同点。方法 采用兔下颌骨牵引模型在牵张不同时期取牵引组织用免疫组化和RT-PCR检测ACTA、TGFβ1蛋白及mRNA在不同时期的表达。结果 牵引过程开始ACT A mRNA的表达量逐渐上升，固定10d及20d达峰值，ACT A蛋白主要分布在成骨细胞内。延迟期末TGFβ1表达量达峰值，其蛋白主要分布于间质及间质细胞。结论 在兔下颌骨牵引过程中ACT A与TGFβ1的作用有很大不同，二者联合可能促进新骨形成。

The expression of activin A and transforming growth factor-β1 during rabbit mandibual distraction osteogenesis

OBJECTIVE: To examine the expression of activin A (ACT A) and transforming growth factor-beta 1 (TGF-beta 1) during mandibular lengthening and elucidate the difference between the role of ACT A and TGF-beta 1 during mandibular distraction osteogenesis. METHOD: Skeletally mature white new zealand rabbits were established right mandibular distraction osteogenesis model. The regenerating tissue of animals' lengthened mandibes were harvested at different time points to have immunohistochemistric research of ACT A, TGF-beta 1 protein and analysis ACT A, TGF-beta 1 mRNA by using RT-PCR semiquantitative mean. RESULTS: AT the end of latency period day, positive stain of ACT A were found in the osteoblasts while positive stain of TGF-beta 1 was found in mesenchymal cells. At the end of distraction phase, fibrosis tissue had no stain of ACT A, but had strong stain of TGF-beta 1. At the period of fixation days of 20 days, both cytoplasm of osteoblasts and extracellular matrix in primary mineralization front were strongly stained of ACT A. The osteoblasts, osteoid and osteocytes in peripheral new bone zone were moderately stained of ACT A. TGF-beta 1 had strongly positive stained in fibrosis zone and weekly positive stained in primary mineralization front and peripheral new bone zone. There were also broad activin A stains in cytoplasm of osteoblasts, osteoid and cytoplasm of ACT A, TGF-beta 1 in osteocytes after distraction for 30 days. Activin A mRNA began to express at the end of latency period. Expression for activin A mRNA increased gradually along with the beginning of distraction and at the peak in distraction of 10 days and 20 days, while TGF beta 1 mRNA increased at the peak at the end of latency period. CONCLUSION: ACT A and TGF beta 1 have different role during rabbit mandibular distraction osteogenesis.