肌腱愈合过程中转化生长因子β1基因表达的变化

目的研究兔屈趾肌腱Ⅱ区伤口愈合过程中转化生长因子β1（transforming growth factorpβ1，TGF-β1）基因表达的变化。方法取成年新西兰大白兔60只，体重4．0～4．5kg，将左前中趾屈趾深肌腱切断并采用标准Kessler缝合法修复作为实验组，分别于术后1、7、14、21、28及56d获取肌腱及腱鞘进行观察，每个时间点取10只；同一动物的右前肢正常肌腱及腱鞘作为对照组。采用原位杂交和免疫组织化学染色分析TGF—β1的表达情况。结果原位杂交结果示：实验组TGF—β1mRNA在术后1d开始上调，14～21d达高峰，56d保持较高水平；对照组存在TGF—β1mRNA的表达，但表达水平较低；实验组各时间点TGF—β1mRNA表达与对照组比较，差异均有统计学意义（P〈O．05）。免疫组织化学染色：实验组术后1d，TGF—β1蛋白信号的表达增加，14～21d达高峰，56d仍保持一定水平；对照组术后各时间点存在TGF—β1蛋白信号表达，但表达水平较低。结论正常无损伤的肌腱和腱鞘能产生TGF—β1，当肌腱损伤后，细胞因子被激活，增加的细胞因子主要由肌腱细胞与腱鞘细胞产生，与肌腱的内、外源性愈合机制是一致的。

GENE EXPRESSION OF TRANSFORMING GROWTH FACTOR β1 IN ZONE Ⅱ FLEXOR TENDON WOUND HEALING OF RABBIT

OBJECTIVE: To research the gene expression of transforming growth factor beta1 (TGF-beta1) in zone II flexor tendon wound healing of rabbit. METHODS: Sixty New Zealand white rabbits forepaws (left side) underwent complete transection and the middle digit flexor digitorum profundus tendon in zone II were repaired by Kessler methods as the experimental group. The normal right forepaws served as the control group. The tendons and tendon sheaths were harvested at 1, 7, 14, 21, 28 and 56 days after repair (n = 10). The expression patterns of TGF-beta1 were analyzed by in situ hybridization and immunohistochemistry staining methods. RESULTS: The in situ hybridization examination revealed that TGF-beta1 mRNA expression up-regulated at 1 day, reached the peak levels at 14-21 days and remained high levels up to 56 days in the experimental group. The expression of TGF-beta1 mRNA in control group was lower than that in the experimental group, showing statistically significant difference (P < 0.05). The results of immunohistochemical staining was similar to that of in situ hybridization. CONCLUSION: The normal tendon and tendon sheath cells are capable of TGF-beta1 production. The cytokine is activated in tendon wound condition. The up-regulation of this cytokine in both tendon and tendon sheath cells are coincidence with both extrinsic and intrinsic mechanisms for tendon repair.