Abstract: Objective To investigate the characteristics of vocal fold wound healing by studying the changes in histopathology and the major extra cellular matrix(ECM) after vocal fold lamina propria injuring in a rabbit model. Methods Using a telescope for guidance, we made an incision in the middle region of the vocal fold tissue in 12 rabbits. Larynges were harvested at 3, 15, 40 days and 3, 6, 12 months after operation. We performed HE staining for histopathologic research, and used Masson trichrome staining for collagen, Alcian Blue staining for hyaluronic acid and immunohistochemical staining for fibronectin. Results After injury, the formation of new capillaries and inflammatory cells infiltration occurred within 15 days, fibroblasts increased significantly form 3 days to 3 months, fibrous tissues persistently increased from 40 days to 12 months, 12 months after injuring, the vocal folds had no hierarchical structure in local position. In addition, the content of collagen were significantly higher than normal(P<0.05) after injury, collagen had an irregular disordered distribution in the lamina propria. Hyaluronic acid had less increase, its content and distribution showed no significant difference with the normal control. Fibronectin scattered in the lamina propria, its levels were obviously higher than normal(P<0.05) from 40 days to 12 months after injury. Conclusion In the early and middle period of vocal fold wound healing, the ECM in the lamina propria increased, collagen increased significantly and deposited disorderly, hyaluronic acid less increased, fibronectin obviously increased; in the late period, collagen and fibronectin levels were continuously higher than normal, disordered collagen fibers arranged in vocal fold scar.

Key words: vocal fold injury, extra cellular matrix, histology, reparation