Valenga Marcelo Henrique, Vitorasso Renato de Lima, Rodrigues Thiago Guimarães, Pazetti Rogério, Cardoso Paulo Francisco Guerreiro, Moriya Henrique Takachi, Aoki Fabio Gava
Biomedical Engineering Laboratory (LEB), Escola Politécnica, University of São Paulo, São Paulo - SP, Brazil.
Thoracic Surgery Research Laboratory (LIM-61), Instituto do Coração (InCor), University of São Paulo, São Paulo - SP, Brazil.
Artif Organs. 2020 May;44(5):504-512. doi: 10.1111/aor.13604. Epub 2019 Dec 15.
Mechanical evaluation of tracheal grafts is of great relevance for transplant research. Although there are some publications demonstrating different techniques of tracheal mechanical evaluation, there is still no definitive or preferred protocol available. Here, we present a simple image processing acquisition system that can be used for in vivo experiments. Six male Wistar rats were submitted to orotracheal intubation and a longitudinal incision was made to expose the trachea. Images of tracheae were acquired from a video camera in different scenarios of bronchoconstriction using methacholine (MCh) (Basal, PBS, MCh 30 μg/kg, MCh 300 μg/kg, and postmetabolized) during imposed-inspiration and imposed-expiration. The area variation ratio (the ratio between areas during expiration vs. inspiration) was 1.1× for the Basal group, while the ratio for MCh 300 µg/kg was 6.5×. The area variation of imaged tracheae was statistically significant at the dose of MCh 300 µg/kg for imposed-inspiration versus imposed-expiration (P = .002). Likewise, elastance data of respiratory mechanics indicated a statistically significant difference at the dose of MCh 300 µg/kg for imposed-inspiration versus imposed-expiration (P = .026). Our image processing analysis protocol presented corresponding behavior when compared to mechanical parameters of the respiratory system. In addition, our image acquisition system was able to highlight the differences between imposed-inspiration and imposed-expiration. Image analysis of the tracheal area variation seems to be in agreement with the elastance of the respiratory system. Taken together, these observations may help future studies of tracheal transplantation for in situ assessment of graft patency.
气管移植物的力学评估对移植研究具有重要意义。尽管有一些出版物展示了气管力学评估的不同技术，但仍然没有确定的或首选的方案。在此，我们介绍一种可用于体内实验的简单图像处理采集系统。六只雄性Wistar大鼠接受经口气管插管，并做纵向切口以暴露气管。在强制吸气和强制呼气期间，使用乙酰甲胆碱（MCh）（基础状态、PBS、30μg/kg MCh、300μg/kg MCh以及代谢后）在不同支气管收缩情况下，通过摄像机采集气管图像。基础组的面积变化率（呼气与吸气时面积之比）为1.1倍，而300μg/kg MCh组的该比率为6.5倍。在300μg/kg MCh剂量下，成像气管的面积变化在强制吸气与强制呼气之间具有统计学意义（P = 0.002）。同样，呼吸力学的弹性数据表明，在300μg/kg MCh剂量下，强制吸气与强制呼气之间存在统计学显著差异（P = 0.026）。与呼吸系统的力学参数相比，我们的图像处理分析方案呈现出相应的行为。此外，我们的图像采集系统能够突出强制吸气和强制呼气之间的差异。气管面积变化的图像分析似乎与呼吸系统的弹性一致。综上所述，这些观察结果可能有助于未来气管移植原位评估移植物通畅性的研究。
