In vivo study of biological effects of photodynamic therapy on cervical cancer

In 1999, Ramon et al examined the effects of δ-aminolevulinic acid (δ-ALA) on two cervical cancer cell lines (HeLa and CaLo) and normal cervical cells. The results reported additionally support the proposal that Photodynamic Therapy (PDT) could be an effective tool for treatment of cervical cancer (CeCa) by protoporphyrin IX (PpIX) accumulation. This cancer is in México considered a problem of public health. In this project PDT was applied in a CeCa mouse model by implantation of HeLa cells in nu/nu mice, exposing it to δ-ALA to a dose that induces the greater concentration of PpIX by intratumoral and oral route, as well as the power and the number of optimal irradiations at 630?nm with a diode laser; verifying which of the used doses does not produce significant damage to the organs by means of histopatologic techniques: liver, spleen, brain and kidney, the determination of reactive substances to tiobarbituric acid (TBAR'S) and measured the amount of residual δ-ALA, the size of the tumor at the beginning and at the end of the application of the PDT. Results. The cervical cancer mouse model is developed by implantation of 1,5 million HeLa cells, appearing at 15 days. The dose of δ-ALA that induces the greater concentration of PpIX in the tumor by intratumoral route was 40?mg of δ-ALA/kg body weight and for oral route it was 20?mg of δ-ALA/kg body weight, both routes did not present significant damage in the organs and according to the Analysis of Bifactorial Variance for the doses of δ-ALA and the organs no difference exists (p > 0.05). The power of the used laser was 150?J/cm² and 250?J/cm², both applied by intratumoral and oral route after the δ-ALA administration. The greater diminution in the size of the tumor (53%) was by the δ-ALA oral route administration to a power of 150?J/cm² with 5?irradiations in intervals of 48?h.