Abstract
For a rational therapeutic use of photodynamic therapy (PDT) in the oral region, histologic changes were quantified and the influence to cell proliferation was assessed in normal C3H tongues subjected to the following protocols: a) 2.5 mg/kg hematoporphyrin oligomers-24hr interval-180 J/cm2 or 15 mJ/pulse/cm2, 20 min (630nm light emitted from pulsed Nd: YAG dye laser, 10Hz); b) 10-24-180; c) 20-24-180; d) 20-24-90; and e) 20-3-180.
One day post-PDT, distortion of lingual papillae, loss of keratohyalin granules, blistering, edema formation, neutrophilic infiltration and congestion of blood vessels were observed, the severity being a function of increased photo-sensitizer and light dose and decreased time interval between them. Computer assisted image analysis revealed increase in the absolute cross-sectional areas, the connective tissues occupying the major portion. Counting delineated a decrease in the number of blood vessels. Bromodeoxyuridine immunohistochemistry indicated a stimulative effect on cell proliferation with a rise in the number of S phase cells especially in the 20-24-90 and 20-24-180 groups.
Restoration of quantitative data to the untreated control levels was attained 5 days post-PDT except for the 20-3-180 group whose further evaluation was deferred due to deaths possibly from traumatic shock. Residual edema and chronic inflammatory reaction were persistent in some mice.
Under the commonly employed doses, as a-d, above, PDT may be rendered safely in the mouse tongue model.
