Avaliação dos efeitos da hipertermoterapia por ultrasom associada a agentes antiangiogênicos no tratamento do tumor experimental de Walker

Abstract

The traditional methods of cancer treatment, like the chemotherapy and radiotherapy, even though they are effective in many types of tumours, they find frequently resistant neoplasic cells’ population, beyond presenting a low security margin to the patients. The hyperthermia use associated to the chemotherapy and radiotherapy are plenty mentioned as profitable in the specialist literature, especially in patients with cancer in advanced stage, submitted previously to the classic methods of the treatment. The tissues’ heat insertion through the continuous ultrasound becomes the procedure faster and with proved efficacy. The antiangiogenic use also is being related like effective in the specialist literature and, at this moment, the substances’ list has grown vastly. The study of the hyperthermia action associated to antiangiogenic agents has been suggested, once the tumour vessels are dilated, would not promote the temperature reduction in the tumour vessels and, therefore, the effects of this association would be more intense than in the normal tissue, what might contribute to the death cell. The study objective is to evaluate the antitumor and antiangiogenic effect of the hyperthermia induced by isolated ultrasound and combined with etoricoxibe and pegaptanibe in the 256 Walker carcinossarcoma implanted in the subcutaneous back screen of mouse by using the hyperthermia experimental model by ultrasound, like the hyperthermia effects study by isolated ultrasound and linked with etoricoxibe and pegaptanibe, in the tumour angiogenesis. The method used describes the insertion of 256 Walker Tumour cells in the back of male Wistar mouse. The animals were treated with hyperthermia applied through the ultrasound equipment, kept to a 45º C level during five minutes in the third day after the inoculation and also treated with etoricoxibe and pegaptanibe by oral and intraperitoneal respectively since the inoculation day. Each animal group was submitted to a tumour growth measurement during a period of 30 days, as well as also a vascular microdensity evaluation through a photographic mesoscopic study, validated by the microscopic study. The heat application through the ultrasound equipment demonstrated efficiency and agility. The hyperthermia, the etoricoxibe and the pegaptanibe showed antiangiogenic capacity, expressed by the over life curve, and also by the vascular microdensity evaluation. Particularly, the isolated hyperthermia showed a significative antiangiogenic effect in the tumour growth curve and also in the decreasing of the micro vascular density. The association between the hyperthermia and the pegaptanibe demonstrated a greater efficiency in the reducing of the micro vascular density than the other groups. The hyperthermia application model generated by the ultrasound equipment in the continuous modality was satisfactory, demonstrating by being effective as much in the reducing of the tumour growth as in the decreasing of the micro vascular density.