Easwaran Meena, Martinez Joshua D, Ramirez Daniel J, Gall Phillip A, Erickson-DiRenzo Elizabeth
Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA, USA.
Toxicol Rep. 2021 Apr 19;8:920-937. doi: 10.1016/j.toxrep.2021.04.007. eCollection 2021.
The larynx is an essential organ in the respiratory tract and necessary for airway protection, respiration, and phonation. Cigarette smoking is a significant risk factor associated with benign and malignant laryngeal diseases. Despite this association, the underlying mechanisms by which cigarette smoke (CS) drives disease development are not well elucidated. In the current study, we developed a short-term murine whole body inhalation model to evaluate the first CS-induced cellular responses in the glottic [i.e. vocal fold (VF)] and subglottic regions of the larynx. Specifically, we investigated epithelial cell proliferation, cell death, surface topography, and mucus production, at various time points (1 day, 5 days, 10 days) after ∼ 2 h exposure to 3R4F cigarettes (Delivered dose: 5.6968 mg/kg per cigarette) and following cessation for 5 days after a 5 day CS exposure (CSE). CSE elevated levels of BrdU labeled proliferative cells and p63 labeled epithelial basal cells on day 1 in the VF. CSE increased proliferative cells in the subglottis at days 5, 10 and following cessation in the subglottis. Cleaved caspase-3 apoptotic activity was absent in VF at all time points and increased at day 1 in the subglottis. Evaluation of the VF surface by scanning electron microscopy (SEM) revealed significant epithelial microprojection damage at day 10 and early signs of necrosis at days 5 and 10 post-CSE. SEM visualizations additionally indicated the presence of deformed cilia at days 5 and 10 after CSE and post-cessation in the respiratory epithelium lined subglottis. In terms of mucin content, the impact of short-term CSE was observed only at day 10, with decreasing acidic mucin levels and increasing neutral mucin levels. Overall, these findings reveal regional differences in murine laryngeal cellular responses following short-term CSE and provide insight into potential mechanisms underlying CS-induced laryngeal disease development.
喉是呼吸道中的一个重要器官，对于气道保护、呼吸和发声至关重要。吸烟是与良性和恶性喉疾病相关的一个重要危险因素。尽管存在这种关联，但香烟烟雾（CS）驱动疾病发展的潜在机制尚未得到充分阐明。在当前的研究中，我们建立了一种短期小鼠全身吸入模型，以评估CS诱导的喉声门[即声带（VF）]和声门下区域的首批细胞反应。具体而言，我们在暴露于3R4F香烟约2小时后（每支香烟递送剂量：5.6968毫克/千克）的不同时间点（1天、5天、10天）以及在5天CS暴露（CSE）后停止暴露5天后，研究了上皮细胞增殖、细胞死亡、表面形貌和黏液分泌情况。CSE在第1天时使VF中BrdU标记的增殖细胞和p63标记的上皮基底细胞水平升高。CSE在第5天、第10天以及声门下停止暴露后增加了声门下的增殖细胞。在所有时间点，VF中均未检测到裂解的半胱天冬酶-3凋亡活性，而在声门下第1天时增加。通过扫描电子显微镜（SEM）对VF表面进行评估发现，在CSE后第10天出现明显的上皮微突起损伤，在第5天和第10天出现早期坏死迹象。SEM观察还表明，在CSE后第5天和第10天以及停止暴露后，声门下呼吸道上皮中的纤毛出现变形。就黏蛋白含量而言，仅在第10天观察到短期CSE的影响，酸性黏蛋白水平降低，中性黏蛋白水平升高。总体而言，这些发现揭示了短期CSE后小鼠喉细胞反应的区域差异，并为CS诱导的喉疾病发展的潜在机制提供了见解。
