RESUMO
A Terapia Fotodinâmica (PDT) tem-se mostrado uma técnica seletiva promissora no tratamento do câncer. Após injeção intravenosa de um sensibilizador, que é retido por várias horas em células neoplásias, o tecido é irradiado por um laser, e devido a um mecanismo de transferência de energia não radiativa, agentes citotóxicos são produzidos, induzindo as células tumorais à morte. A técnica de hiperoxigenação hiperbárica (HBO) permite elevar o suprimento de oxigênio molecular, nos tecidos tumorais permitindo potencializar a PDT. Para avaliar o efeito combinado (PDT+HBO), desenvolvemos um modelo experimental que consiste na irradiação de tumores sólidos subcutâneos em dorso de ratos.
Photodynamic Therapy (PDT) have been demonstrated a very promising selectivity potential in cancer treatment. After an intravenous infusion of sensitizes, which is retained for severa! hours inside the neoplasic cells, the tissue is irradiated with a laser beam, and due a non-radiactive transfer mechanism, cytotoxic agents are produced, inducing death of the tumor cells. Hyperbaric hyperoxia (HBO) allows the tissues to achieve high supply of molecular oxygen. ln order to evaluate this combined effect of both therapies an experimental model was developed, creating a tumor mass in the dorsal subcutaneous tissue of rats.
Assuntos
Animais , Ratos , Fotoquimioterapia , Lasers/uso terapêutico , Neoplasias/tratamento farmacológico , Neoplasias/radioterapia , Oxigenoterapia Hiperbárica , Hematoporfirinas/uso terapêuticoRESUMO
Neurogenic pulmonary edema was induced in rats by bilateral cervical vagotomy. One hour after surgery, 25 animals were placed in an experimental hyperbaric chamber and allowed to breathe oxygen at 1.8 absolute atmospheres for 325 min. Vagotomized controls (N = 25) breathed atmospheric air. Twenty-four h after vagotomy, arterial blood samples were obtained and the lungs removed. Lungs were weighed wet and dry and lung indexes were calculated for each animal by dividing lung wet weight and dry weight by total body weight. There was no statistical difference in total lung weight or total water among groups. However, the dry lung index was about 20% lower in oxygen-treated animals than in controls. There was no difference between hyperbaric oxygen-treated animals and non-vagotomized normal animals, but vagotomized air-breathing controls differed significantly from non-vagotomized animals (P less than 0.05). These results strongly suggest a slower formation of pulmonary edema in the hyperbaric oxygen-treated group.