RESUMEN
<p><b>OBJECTIVE</b>To investigate the role of nasal mucosa fibrosis on radiation induced nasal mucosa injury.</p><p><b>METHODS</b>Seventy two male rats were randomly divided into two groups, control group and irradiation injured group (radiation dose were 40 Gy); the rats were killed 1 week, 2 weeks, 4 weeks, 8 weeks, 3 months and 6 months after the finish of radiation. The middle turbinates of the animals were removed. The pathological change of the nasal mucosa were observed with scanning electron microscope, transmission electron microscope, hematoxylin and eosin (HE), alcian blue-periodic acid-Schif (AB-PAS), and Masson Trichrome (MT). The Hyp content in nasal mucosa was measured with chemo-chromatometry.</p><p><b>RESULTS</b>After radiation, the pathological characteristics in early stage (within 4 weeks) was acute inflammatory reaction. The repair of nasal mucosa started 4 weeks after radiation, lasted to 6 months. The deposition of collagen in nasal mucosa could be found 1 week after irradiation and increased gradually.</p><p><b>CONCLUSION</b>Irradiation could induce a serials of pathological changes on nasal mucosa. The nasal mucosa fibrosis may be one of the reasons of persistent irradiation induced nasal mucosa injury.</p>