Ultraviolet light and photodynamic therapy induce apoptosis in nasal polyps

Abstract

Intranasal phototherapy has been found to be effective for the treatment of nasal polyposis (NP) therefore the aim was to investigate the apoptosis inducing effect of phototherapy in NP. In this ex vivo study nasal polyp tissue was surgically collected from 21 consecutive patients with chronic rhinosinusitis (CRS) associated with NP. The removed polyps were cut into pieces and tissue samples were irradiated in vitro by different doses of combined ultraviolet and visible light (UV/VIS: 280-650 nm) and by selective ultraviolet and visible light (sUV/VIS: 295-650 nm). Photodynamic therapy (PDT) was performed by presensitizing tissue samples with 5-delta-aminolevulinic acid (DALA) then irradiated with visible light (VIS: 395-650 nm). Tunel assay was applied to detect apoptosis of epithelial and inflammatory cells in irradiated and control nasal polyp tissue samples. UV/VIS light significantly increased epithelial cell and subepithelial leukocyte apoptosis compared to control groups. PDT treatment showed the highest surface epithelial cell as well as subepithelial leukocyte apoptosis compared to all other groups. Intranasal phototherapy may serve as a new potential therapeutical method in treatment of NP.