Chen Lili, Li Chenlong, He Aijuan, Tong Hua, Lu Xinyu, Yang Run, Chen Xin, Wu Xu, Wang Xin, Wang Shuqi, Ma Jing, Fu Yaoyao, Zhang Tianyu
ENT institute, Eye & ENT Hospital, Fudan University, Shanghai, China.
Department of Facial Plastic and Reconstructive Surgery, Eye & ENT Hospital, Fudan University, Shanghai, China.
Laryngoscope. 2023 Jan;133(1):88-94. doi: 10.1002/lary.30124. Epub 2022 Apr 6.
Ear molding is an emerging technique that can correct auricular deformities. Treatment initiation time is the most important prognostic determinant of ear molding. Here, we aimed to examine why auricular cartilage plasticity appeared to diminish with age. Thus, we characterized age-related changes in the biomechanical, biochemical, and morphological properties of auricular cartilage.
New Zealand rabbits were used as the experimental animal. We examined immature [postnatal 0 day (P0), 5 days (P5), 15 days (P15)], young [2 months (2M)], and mature [6 months (6M)] rabbits. Rabbits' ears were splinted and folded using adhesive fixation strips. Folding duration ranged from 1 day to 5 days to 10 days. Photographs were taken to calculate the retained fold angle. Cartilage morphology and extracellular matrix (ECM) content were examined histologically (using hematoxylin-eosin, Safranin O, elastic Van Gieson, and Masson's trichrome). Water content, DNA content, and cell density were also analyzed. Biomechanical properties were measured using a Nano indenter.
Immature ears had smaller angles after strip removal, and the angled deformation lasted a longer time. Cartilage matrix compositions, including glycosaminoglycan (GAG), elastin fiber, and collagen, increased over development. The water content, DNA content, and cell density decreased with age. Young's modulus was significantly higher in mature cartilage.
Here, we successfully established an animal model of ear molding and demonstrated that immature cartilage was associated with better plasticity. We also found that the cartilage's biomechanical property increased with the accumulation of ECM. The biomechanical change could underlie age-related shape plasticity.
NA Laryngoscope, 133:88-94, 2023.
耳部塑形是一种可矫正耳廓畸形的新兴技术。治疗起始时间是耳部塑形最重要的预后决定因素。在此，我们旨在探究为何耳廓软骨可塑性似乎会随年龄增长而降低。因此，我们对耳廓软骨的生物力学、生化和形态学特性的年龄相关变化进行了表征。
将新西兰兔用作实验动物。我们研究了未成熟[出生后0天（P0）、5天（P5）、15天（P15）]、幼年[2个月（2M）]和成年[6个月（6M）]的兔子。使用粘性固定条对兔耳进行夹板固定和折叠。折叠持续时间从1天到5天再到10天不等。拍摄照片以计算保留的折叠角度。通过组织学方法（使用苏木精 - 伊红、番红O、弹性维多利亚蓝和马森三色染色法）检查软骨形态和细胞外基质（ECM）含量。还分析了水分含量、DNA含量和细胞密度。使用纳米压痕仪测量生物力学特性。
去除固定条后，未成熟耳的角度较小，且角度变形持续时间更长。软骨基质成分，包括糖胺聚糖（GAG）、弹性纤维和胶原蛋白，在发育过程中增加。水分含量、DNA含量和细胞密度随年龄增长而降低。成年软骨的杨氏模量显著更高。
在此，我们成功建立了耳部塑形动物模型，并证明未成熟软骨具有更好的可塑性。我们还发现软骨的生物力学特性随ECM的积累而增加。生物力学变化可能是与年龄相关的形状可塑性的基础。
NA 《喉镜》，2023年，第133卷，第88 - 94页
