Detection of macula flava cells proliferation after vocal fold injury

OBJECTIVES: The role of macula flava cells in vocal fold injury repair remains unknown. This study aimed to determine whether they proliferate following vocal fold injury. METHODS: Twenty male Sprague-Dawley rats were divided into control group (n = 5) and experimental group (n = 15). The left vocal fold was injured in rats of the experimental group. The rats were euthanized on postoperative day 1, 3, and 7. Hematoxylin and Eosin (HE) staining was used to examine healing process. Multicolor immunofluorescence was used to detect cell types: proliferating cells (5-Ethynyl-2'-deoxyuridine, EdU), macula flava cells (Glial Fibrillary Acidic Protein, GFAP), and fibroblasts (vimentin). RESULTS: One day post-injury, the injured vocal fold lacked an epithelial layer and exhibited tissue edema. Three-day post-injury, epithelial cells had begun to cover the injured region. By seven-day post-injury, the injured region fully covered by epithelial cells and displayed atrophy. EdU-positive fibroblasts in the lamina propria significantly increased at day 3, followed by a pronounced decrease at day 7 (p < 0.05). The macula flava cells of injured vocal fold proliferated at day 3 and 7 (p = 0.008). CONCLUSION: Vocal fold injuries were repaired within seven days. The results indicated that proliferate behavior differs between macula flava cells and fibroblasts during vocal fold injury repair. Macula flava cells may be also involved in the injury repair.