Department of Otolaryngology, Medical University of Warsaw, Banach 1a, 02-097, Warsaw, Poland.
Department of General and Experimental Pathology, Medical University of Białystok, Mickiewicza 2c, 15-222, Białystok, Poland.
Int J Pediatr Otorhinolaryngol. 2020 Sep;136:110196. doi: 10.1016/j.ijporl.2020.110196. Epub 2020 Jun 24.
Type III collagen plays significant role in skin wound healing, forming provisional matrix guiding the inflammatory cells and fibroblasts into the wound site. Our preliminary study performed on rat's tympanic membrane (TM) using Rat Wound Healing RT2 Profiler PCR Array revealed up-regulated expression of collagen type III α1 chain mRNA also during healing of TM. This study was undertaken to confirm and evaluate collagen type III protein expression and distribution during TM healing process.
Sixty rats were used, of which 10 served as controls and the others had their TM perforated. The experimental animals were divided into five subgroups on the basis of time points (03, 06, 09, 14, 20 day after injury). Videootoscopy and histology were employed to assess morphology of the healing process. The expression of collagen type III was evaluated using Western blot analysis and its tissue localization was determined by the immunohistochemical method.
The expression of collagen type III remained on the same level as in control TM up to day 06. On day 09 abrupt (p = 0.01) increase of the collagen type III expression was observed and it maintained on the same level to the end of observation period. In perforated TM collagen type III was detected in the healing area along the perforation border and around dilated blood vessels. On day 14 and 20 collagen type III was found in the connective tissue filling up the TM previous defect.
Taking into consideration our recent and previous data, as well as results obtained by other authors, is seems possible that the increase of collagen type III expression in the late stage of TM healing contributes to proper scar formation.
III 型胶原在皮肤伤口愈合中起着重要作用，形成临时基质，引导炎症细胞和成纤维细胞进入伤口部位。我们之前在大鼠鼓膜（TM）上进行的研究使用 Rat Wound Healing RT2 Profiler PCR Array 显示，在 TM 愈合过程中，III 型胶原 α1 链 mRNA 的表达也上调。本研究旨在确认和评估 TM 愈合过程中 III 型胶原蛋白的表达和分布。
使用 60 只大鼠，其中 10 只为对照组，其余大鼠的 TM 穿孔。根据时间点（损伤后 03、06、09、14、20 天）将实验动物分为 5 个亚组。视频耳镜和组织学用于评估愈合过程的形态。使用 Western blot 分析评估 III 型胶原的表达，并用免疫组织化学方法确定其组织定位。
在第 06 天之前，III 型胶原的表达与对照组 TM 中的表达水平相同。在第 09 天，观察到 III 型胶原表达突然增加（p=0.01），并在观察期结束时保持相同水平。在穿孔的 TM 中，在穿孔边缘和扩张的血管周围的愈合区域检测到 III 型胶原。在第 14 天和第 20 天，在填充 TM 先前缺陷的结缔组织中发现 III 型胶原。
考虑到我们最近和之前的数据，以及其他作者的结果，III 型胶原表达在 TM 愈合后期的增加可能有助于适当的瘢痕形成。
