Utility of the F98 rat glioma model for photodynamic therapy.

A syngeneic rat brain tumor model consisting of F98 glioma cells in Fischer rats was investigated for its utility in PDT studies. Results of in vitro studies demonstrated that the F98 cell line was sensitive to ALA-PDT, especially at low light irradiances. Histological examination revealed that F98 tumors share many fundamental characteristics with human GBMs, including rapid growth and infiltrative behavior. ALA-PDT in normal brain showed that high light fluences (26 J) delivered at relatively low powers (10 mW) are capable of causing significant edema. These findings suggest that light irradiation parameters should be chosen carefully when treating tumor-bearing animals. Rats inoculated with F98 cells preincubated in ALA showed a significant survival advantage following light exposure. Taken together, the results suggest that the F98 rat glioma model is appropriate for PDT studies of malignant gliomas.