Yang-Soo Kim, Department of Orthopedic Surgery, Seoul St Mary's Hospital, the Catholic University of Korea, 505 Banpo-dong, Seocho-gu, Seoul, Korea, 137-701.
Am J Sports Med. 2013 Oct;41(10):2249-55. doi: 10.1177/0363546513493392. Epub 2013 Jun 20.
Even though apoptosis is known to be closely associated with rotator cuff tears, the differences in apoptosis according to the location within the torn supraspinatus tendon are still unknown.
To elucidate where apoptosis begins within the supraspinatus tendon.
Controlled laboratory study.
Tendon tissues were collected from 14 patients undergoing arthroscopic rotator cuff repair surgery and 7 patients undergoing surgery for proximal humeral fracture who served as controls. In the patients with rotator cuff tears, the samples were harvested at 3 sites: the most lateral torn margin, 1 cm medial from the torn margin, and at the posterior torn corner. Caspase 3/7, 8, and 9 and cytochrome c activities were measured to determine the intracellular apoptosis pathway. Apoptotic cells were determined by in situ TUNEL (terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling) staining, and immunohistochemistry was performed.
The apoptotic activities of tendons from the experimental subjects were significantly higher than those of the controls. There were, however, no significant differences between the 3 sample sites. Immunohistochemistry also revealed strong expression of increased caspase 3/7, 8, and 9 and cytochrome c but no significant difference between them.
This study shows that the intracellular apoptotic pathway is not only through the cell membrane receptor but also via intracellular mitochondria cascade.
Because apoptosis occurs regardless of the location within the rotator cuff, debridement of the torn margin to obtain a healthy tendon may not be needed. Further study should focus on not only the technique of tying the torn tendon back to the bone but also biological augmentation to reverse or prevent further apoptosis within rotator cuff tendon.
尽管细胞凋亡与肩袖撕裂密切相关，但撕裂的冈上肌腱内的细胞凋亡的位置差异仍不清楚。
阐明冈上肌腱内的细胞凋亡从何处开始。
对照性实验室研究。
从 14 例行关节镜肩袖修复术的患者和 7 例行肱骨近端骨折手术的患者（作为对照）中采集肌腱组织。在肩袖撕裂患者中，在 3 个部位采集样本：最外侧撕裂边缘、撕裂边缘内侧 1cm 处和后撕裂角。通过测定 caspase 3/7、8 和 9 及细胞色素 c 的活性来确定细胞内凋亡途径。通过原位 TUNEL（末端脱氧核苷酸转移酶介导的 dUTP-生物素缺口末端标记）染色和免疫组织化学检测来确定凋亡细胞。
实验组肌腱的凋亡活性明显高于对照组，但 3 个样本部位之间无显著差异。免疫组织化学也显示 caspase 3/7、8 和 9 及细胞色素 c 的表达增加，但无显著差异。
本研究表明，细胞内凋亡途径不仅通过细胞膜受体，还通过细胞内线粒体级联。
由于细胞凋亡发生在肩袖内的任何位置，因此可能不需要切除撕裂边缘以获得健康的肌腱。进一步的研究应不仅关注将撕裂的肌腱重新缝合到骨头上的技术，还应关注通过生物增强来逆转或防止肩袖肌腱内进一步的细胞凋亡。
