Centre de Recherche du CHU de Québec-CHUL, Université Laval, 2705 boulevard Laurier, Quebec City, QC, Canada, G1V 4G2.
J Orthop Res. 2014 Feb;32(2):279-85. doi: 10.1002/jor.22504. Epub 2013 Oct 25.
Macrophages are present in large numbers and display specific and distinct phenotypes during the various phases of tissue repair. However, their role following tendon injury and during repair has never been investigated. We injected C57BL/6 mice daily for 4 days with liposome-encapsulated clodronate to deplete circulating monocytes/macrophages. Placebo mice were injected with PBS. The left Achilles tendons of the mice were transversely sectioned and sutured using the 8-strand technique. Macrophage accumulation and cell proliferation were significantly lower in the tendons of clodronate-treated mice than in those of PBS-treated mice on days 3 and 7 post-injury. TGF-β1 staining was significantly more intense in the tendons of PBS-treated mice on day 7 post-injury. Edema and the dry mass of the Achilles tendons were also higher in the PBS-treated mice on days 7 and 14 post-injury. No differences in absolute strength and stiffness were observed, but Young's modulus and maximal stress were significantly greater for tendons from the clodronate-treated mice than those from PBS-treated mice after 14 days of tendon repair. Overall, our findings showed that macrophages promote cell proliferation and extracellular matrix accumulation but their presence leads to inferior ultimate tensile strength of the Achilles tendons.
巨噬细胞数量众多，在组织修复的各个阶段表现出特定而明显的表型。然而，它们在跟腱损伤后的作用及其在修复过程中的作用从未被研究过。我们每天给 C57BL/6 小鼠注射 4 天脂质体包裹的氯膦酸盐以耗尽循环单核细胞/巨噬细胞。给安慰剂小鼠注射 PBS。用 8 股技术将小鼠的左跟腱横向切开并缝合。与 PBS 处理的小鼠相比，在损伤后第 3 和第 7 天，氯膦酸盐处理的小鼠的肌腱中巨噬细胞积累和细胞增殖明显更低。在损伤后第 7 天，PBS 处理的小鼠的 TGF-β1 染色明显更强烈。在损伤后第 7 和 14 天，PBS 处理的小鼠的肌腱水肿和干质量也更高。绝对强度和硬度没有差异，但在肌腱修复 14 天后，来自氯膦酸盐处理的小鼠的肌腱的杨氏模量和最大应力明显大于来自 PBS 处理的小鼠的肌腱。总的来说，我们的研究结果表明，巨噬细胞促进细胞增殖和细胞外基质积累，但它们的存在导致跟腱的最终拉伸强度降低。
