State Key Laboratory of Oral Diseases & National Clinical Research Centre for Oral Diseases & Department of Oral and Maxillofacial Surgery, West China Hospital of Stomatology, Sichuan University, 14 Ren Min Nan Road, Chengdu, 610041, P. R. China.
Sci Rep. 2018 Jul 13;8(1):10613. doi: 10.1038/s41598-018-28917-6.
Craniofacial muscles drive critical functions in the head, including speech, feeding and expression. Compared with their counterparts in trunk and limbs, craniofacial muscles are of distinct embryonic origins, which might consequently lead to different growth patterns and regenerative potential. In this study, rat levator veli palatini muscle and masseter muscle were compared with tibialis anterior muscle in their response to exogenous Wnt7a stimulus, which has been proved effective in promoting muscle regeneration in the limbs. Histological, cellular and molecular analyses were performed both under basal condition and after a single dose injection of recombinant human Wnt7a. Under basal condition, levator veli palatini muscle demonstrated considerably more satellite cells than the others. After Wnt7a administration, regeneration-related activities, including satellite cell expansion, myofiber hyperplasia and hypertrophy were generally observed in all three muscles, but with obvious differences in the extent. The composition of fast/slow myofibers underwent substantial alterations, and the pattern varied among the three muscles. Location-specific alterations in the expression level of core components in planar cell polarity pathway, Akt/mTOR pathway and myostatin pathway were also observed. In conclusion, both craniofacial and limb muscles could be effectively expanded by exogenous Wnt7a stimulus, but muscle-to-muscle variations in response patterns existed.
颅面肌肉在头部驱动着关键功能，包括言语、进食和表情。与躯干和四肢的肌肉相比，颅面肌肉具有明显不同的胚胎起源，这可能导致不同的生长模式和再生潜力。在这项研究中，我们比较了大鼠的腭帆提肌和咬肌与比目鱼肌对外源性 Wnt7a 刺激的反应，Wnt7a 已被证明能有效促进四肢的肌肉再生。在基础状态和单次注射重组人 Wnt7a 后，我们进行了组织学、细胞学和分子学分析。在基础状态下，腭帆提肌中的卫星细胞数量明显多于其他两种肌肉。在 Wnt7a 给药后，所有三种肌肉都观察到了与再生相关的活动，包括卫星细胞扩增、肌纤维增生和肥大，但程度上存在明显差异。快/慢肌纤维的组成发生了显著变化，而且三种肌肉的变化模式也不同。平面细胞极性通路、Akt/mTOR 通路和肌肉生长抑制素通路的核心组成部分的表达水平在特定部位也发生了改变。总之，外源性 Wnt7a 刺激可以有效地扩张颅面肌肉和四肢肌肉，但肌肉之间的反应模式存在差异。
