实验性骨延长区TGF-β_(1)的基因表达和细胞定位

Expression and localization of TGF-β_(1) gene in the lengthened segment of goat tibia during the experimental lengthening after metaphysiotomy

目的 了解骨延长过程中TGF β1 基因在骨延长区组织细胞的表达和定位 ,从分子水平探讨延长区骨修复的机制。方法 采用胫骨上干骺端截骨延长 (1.0mm d)动物模型 ,14只山羊分 7个时相点取材。通过延长区组织冰冻切片 ,TGF β1 地高辛标记的cDNA探针原位杂交。结果 延长早期延长区阳性表达细胞逐渐增加 (15d)至最高峰 ,此阶段主要定位于增生的纤维细胞和血管内皮细胞 ;以后细胞阳性表达率迅速下降 ,定位于延长区骨小梁边缘的成骨细胞。结论 TGF β1 在延长区骨修复过程中具有重要作用 ,提高和维持延长区TGF β1 基因高水平有效表达 ,可能对促进和加快延长区骨愈合具有重要的意义。

Objective To investigate the expression and localization of TGF β 1 gene in the lengthened segment for the mechanism of the bone repairing during bone lengthening at a molecular level. Methods After 14 mature goats were inflicted with metaphysiotomy in their upper tibiae, bone lengthening was carried out at a rate of 1.0 mm/d for 30 d. Samples of lengthened bone tissue were collected from the lengthened segment in all animals at 7 different time points and frozen sections were made. The expression of TGF β 1 mRNA in the sections was detected with in situ hybridization (ISH). Results TGF β 1 mRNA gene positive rate was increased gradually and reached a peak on the 15th d after lengthening. During this period, the gene was localized in proliferated fibroblasts and vascular endothelial cells. From the 20th d, its expression began to decrease rapidly and it was mainly localized in the osteoblasts around bone trabecula in lengthened bone segments. Conclusion TGF β 1 plays an important role in the bone repairing of lengthened segment. To raise and maintain the expression of TGF β 1 mRNA in a high level might be a significant route to enhance and promote bone healing in lengthened segment.