Yoshimura K, Harii K, Asato H, Ueda K, Yamada A
Department of Plastic and Reconstructive Surgery, University of Tokyo, Tokyo, 113, Japan.
J Surg Res. 1998 Sep;79(1):31-8. doi: 10.1006/jsre.1998.5377.
Although a number of studies have examined the morphology and function of experimentally transplanted muscles, immunohistochemical evaluation of clinically transplanted muscles has not been reported. The purpose of this study was to examine clinically transplanted muscles at long periods after transplantation with biochemical markers specific for satellite cell activation and muscle regeneration.
Nine biopsies of muscles transplanted to the paralyzed face were examined. In five cases, the gracilis muscles were transplanted about 1 year after cross face nerve grafting. The other four cases underwent one-stage latissimus dorsi (LD) muscle transplantation. Twelve to 162 months after transplantation, muscle biopsies were harvested in nine cases. In eight cases, secondary corrections of facial expression including debulking of the grafted muscle were required, while another muscle was transplanted in one case because of the failed first operation. As control, six specimens of normal LDs were examined as well. Monoclonal antibodies were employed to visualize myosin heavy chain (MHC) isoforms (slow, fast, and embryonic) and MyoD protein.
Although one specimen exhibited only small, atrophic fibers indicating failed reinnervation, the remaining eight specimens showed regularly distributed fibers and type grouping indicating successful reinnervation. There was no statistically significant difference in fiber area and lesser diameter between normal LDs and transplanted LDs. However, even in these successfully reinnervated muscles, intermediate and small fibers expressing embryonic MHC and small cells expressing MyoD were observed, suggesting that satellite cells were activated for repair of the adjacent fibers.
Muscle adaptation (presumably to denervation), which is a regenerative change accompanied by activation of satellite cells, was still seen even long periods after transplantation. It is concluded that, in microneurovascular human skeletal muscle transfers, there is a wide variation in the time required for reinnervation of individual muscle fibers, and it may be that human muscle fibers cannot be properly reinnervated after denervation has continued for a certain period such as 12 months.
尽管已有多项研究对实验性移植肌肉的形态和功能进行了检测，但临床移植肌肉的免疫组织化学评估尚未见报道。本研究的目的是利用卫星细胞激活和肌肉再生的特异性生化标志物，对临床移植较长时间后的肌肉进行检测。
对9例移植到瘫痪面部的肌肉活检标本进行了检查。其中5例在跨面神经移植术后约1年移植了股薄肌。另外4例接受了一期背阔肌（LD）肌肉移植。移植后12至162个月，对9例患者进行了肌肉活检。8例患者需要对面部表情进行二次矫正，包括对移植肌肉进行减容，1例患者因首次手术失败而再次移植了另一块肌肉。作为对照，还检查了6例正常背阔肌标本。采用单克隆抗体观察肌球蛋白重链（MHC）亚型（慢肌、快肌和胚胎型）和MyoD蛋白。
尽管有1个标本仅显示少量萎缩纤维，提示神经再支配失败，但其余8个标本显示纤维分布规则且有类型分组，提示神经再支配成功。正常背阔肌与移植背阔肌之间的纤维面积和较小直径无统计学显著差异。然而，即使在这些神经再支配成功的肌肉中，也观察到表达胚胎型MHC的中、小纤维和表达MyoD的小细胞，提示卫星细胞被激活以修复相邻纤维。
即使在移植很长时间后，仍可见到肌肉适应性改变（可能是对去神经支配的适应），这是一种伴随卫星细胞激活的再生性变化。得出结论，在显微神经血管化的人体骨骼肌移植中，单个肌纤维重新获得神经支配所需的时间差异很大，并且在去神经支配持续一定时间（如12个月）后，人体肌纤维可能无法得到适当的神经再支配。
