Cell production in injured vocal folds: A rat study

Objectives: Fibroblasts are reported to play an important role in producing the extracellular matrix of the vocal fold. However, no reports have focused on how and where these cells are generated in the vocal fold after injury. To reveal the characteristics of vocal fold cell production, we investigated cell proliferation in the acute phase of wound healing. Methods: Using a telescope for guidance, we made an incision in the middle region of the vocal fold tissue in 24 rats and performed immunohistochemical staining for vimentin, α-smooth muscle actin, and 5-bromo-2-deoxyuridine. Results: After injury, epithelialization occurred with a peak at day 1, and fibroblasts proliferated in the lamina propria with a peak at day 3, whereas those in the macula flava did not show any increased proliferation. Conclusions: It is suggested that the fibroblasts in the macula flava have functions different from those of fibroblasts in the lamina propria and that the macula flava does not serve as a cell source for the vocal fold in response to injury.