Wound healing of nasal mucosa in a rat

Abstract

Background: Postoperative wound healing of the nasal mucosa is a highly organized process. However, this process still has not been fully understood. The present study aimed to establish a wound healing model in a rat and describe histomorphological changes of the nasal mucosa after mechanical injury. Methods: Unilateral wound in the nasal cavity was induced using the brushing technique in 4-week-old, Sprague-Dawley rats. Experimental rats were divided into five groups (n = 7 for each group). Animals were killed 1 hour and 2, 5, 14, and 28 days after injury. The histological sections were examined for inflammatory cell infiltration, goblet, and ciliated cell formation in hematoxylin and eosin staining. The subepithelial and epithelial thicknesses were measured and expressed as the subepithelial thickness index (STI) and epithelial thickness index (ETI). Fibrosis was evaluated by subepithelial fibrosis index (SFI) in Masson's trichrome-stained sections. Results: Respiratory epithelial discontinuity and hemorrhage were observed 1 hour after injury. On day 2, edematous subepithelium and infiltration of neutrophils could be found on the injured site. Day 5 was characterized by the infiltration of monocytes and granulation tissue. SFI and ETI values increased significantly at day 14. Goblet cells and ciliated cells began to regenerate from day 14 and restored to near normal at day 28. Conclusion: Using mechanical injury, the wound healing model of the nasal mucosa was established in a rat. The regeneration of respiratory mucosa was completed on day 28 after injury. (Am J Rhinol Allergy 23, e33-e37, 2009; doi: 10.2500/ajra.2009.23.3390)