肩袖损伤后修复的实验研究

The experimental study of the healing process in the injured rotator cuff

目的观察肩峰下撞击征所致肩袖损伤后的修复反应及碱性成纤维细胞生长因子(basicfibroblastgrowthfactor,bFGF)的表达。方法雄性SD大鼠50只,剪取同侧肩胛冈骨块移位于肩峰底面,建立肩峰下撞击模型,对侧行假手术作为对照。分别于术后第3、7、14、28、56d处死动物,切取整个肩关节,观察冈下肌肌腱的修复反应及bFGF的表达,并使用计算机图像分析系统检测bFGF的表达变化,图像分析结果中光密度值(OD)和阳性面积值分别表示bFGF的表达强度和阳性细胞数。结果所有动物实验侧的冈下肌肌腱均出现滑囊面撕裂,肌腱断端细胞增生,来自肩峰下滑囊的结缔组织覆盖其表面。对照侧冈下肌肌腱完好,仅有少量的腱细胞和滑囊细胞表达bFGF;而实验侧沿腱外膜排列的腱细胞、从肩峰下滑囊迁移的炎细胞和成纤维细胞表达信号增强。结论肌腱损伤后bFGF的表达增强;肩峰下滑囊是肩袖修复的基础和bFGF分泌的主要来源,修补肩袖时应尽量给予保留。

Objective To observe the reparative response and expression of basic fibroblast growth factor (bFGF) protein in the rotator cuff subjected to subacromial impingement. Methods Subacromial impingement of the infraspinatus tendon was experimentally created in 50 male SD rats by thickening the undersurface of the acromion with one platelike bony transplantation of the ipsilateral scapular spine. The contralateral shoulders that had undergone a sham operation were used as controls. The rats were sacrificed at 3, 7, 14, 28, and 56 th day, the whole shoulder joint was removed for detecting bFGF protein and the reparative response in the impinged infraspinatus tendon. Computer image analysis system were used to monitor the expression intensity and numbers of positive cells of bFGF protein. The OD scores and the size of area represent the expression intensity and numbers of positive cells respectively. Results All rats with experimental subacromial impingement showed an infraspinatus tear on the bursal side of the tendon. The shoulders in the control group were found intact without any alteration. There was proliferating cells in the fragmented tendons and vascularised connective tissue covering the area of ruptured area, whose source was the subacromial bursa. Few tenocytes and bursal cells expressed bFGF protein in unwounded tendons. In contrast, tendons subjected to impingement exhibited an increased signal for bFGF protein in both resident tenocytes concentrated along the epitenon and infiltrating fibroblasts and inflammatory cells from the subacromial bursa. Conclusion The bFGF protein is upregulated during tendon healing and the subacromial bursa is the main source of both bFGF secreting and rotator cuff repair; one should preserve as much as possible the subacromial bursa.