Citotoxicity of Photodynamic Therapy with Photodithazine® on epithelial cells culture.

Objectives: Evaluate the cytotoxicity of Phodynamic Therapy using diferent concentrations of Photodithazine® (PDZ) photosensitizer on cultured keratinocytes (HaCat cells).
Methods: Solutions with different concentrations of Photodithazine® (100 and 125 mgl^-1), diluted in culture medium (DMEM), were placed in contact with HaCat cells and incubated in the dark fo 20 min, then were illuminated by a LED device (37.5 J cm^-2). Following experimental conditions were evaluated: G1: P+ L- (photosensitizer control), G2: P+L+ (Photodynamic therapy experimental group) G3: P-L+ (Light control) and G4: P-L- (Positive control), where P: Photodithazine® and L: Light.
Cell proliferation was evaluated by MTT assay; data were analyzed and the groups classified according to the ISO 10993-5 in : 0 - non-cytotoxic (inhibition of 25% less than control group ) , 1 - slightly cytotoxic (inhibition between 25 and 50% compared with the control group ) , 2 - moderately cytotoxic (inhibition between 50 and 75% compared with the control group ) and 3 - strongly cytotoxic (inhibition greater than 75% compared to the control group)
Results: According to the control (G4), G1and G3 were not cytotoxic, showing cell inhibition less than 25%. Experimental group G2 was classified as strongly cytotoxic because caused cell inhibition greater than 75% compared with the control group ( G4)
Conclusions: Photodynamic therapy despite being a promising treatment for superficial fungal infections, is considered toxic for epithelial cells.