The Effects of Photobiomodulation Therapy on Xenopus laevis Embryonic Epithelium

Photobiomodulation therapy (PBMT) is widely used in clinical settings, particularly for treating oral mucositis. Although PBMT has shown promise in aiding tissue healing, its safety and potential effects on tumorigenesis remain controversial. Xenopus laevis (X. laevis) tadpoles have proven to be an effective in vivo model system to study how different therapies affect epithelial biology. Because of this, the goal of this study was to investigate how PBMT influences epithelial tissue in X. laevis tadpoles. X. laevis tadpoles were treated with PBMT three times, every 24 h, using a 660 nm low-level laser at a fluence of 2.08 J/cm² and an irradiance of 0.208 W/cm², resulting in a cumulative dose of 2.25 J. Tadpole tails were then fixed, and the abnormal tissue area was analyzed using fluorescent microscopy. PBMT induced the formation of abnormal tissue structures along the epithelial edges. The altered tissue increased from 0.03% in control tadpoles to 0.37% in PBMT-treated tadpoles (p < 0.0001; Mann-Whitney nonparametric test), and the number of tadpoles displaying this abnormal phenotype increased from 3.8% of control tadpoles to 30.6% of PBMT-treated tadpoles (p < 0.001; chi-squared test). This study demonstrates that PBMT can have significant effects on the epithelial tissue of X. laevis. The PBMT-induced abnormal tissue structures represent a loss of tissue polarization and cellular organization along the tail edge, both of which are essential to maintaining tissue homeostasis. For the first time, we show that X. laevis may provide an in vivo model system for examining the effects and mechanisms of PBMT.