Effect of chayotte (Sechium edule) extract on the biodistribution of technetium‐99m and on the morphometry of red blood cells

Abstract

28 de setembro, 87, Rio de Janeiro, RJ, Brasil, 2055 1-030. bemardo@uerj.br key words: Sechiunz edule, blood cells, technetium-99m, biodistribution, morphometry. summary.The evidence that drugs can affect radiolabeling or biodistribution of red cells in setting of nuclear medicine clinic has with to light only recently. A therapeutic drug can modify the nature/amount of technetium-99m ehTc) radiopharmaceutical bound to blood elements and this may result in a unexpected behavior of the radiopharmaceutical. Chayotte is used as food or as medication in popular medicine. We evaluated the influence of chayotte extract (macerated) on the biodistribution of sodium pertechnetate (gh"Tc04Na) in rats lVistar and on the morphometry of the red blood cells. The animals were treated during 60 days with chayotte extract. After that, Tc04Na was injected and the animals were sacrificed. The organs were isolated and counted in a well counter. The percentages of radioactivity (%AT0 in the organs were calculated. The analysis of the results have shown that there was a decrease of %AT1 in the lungs, stomach and thyroid. Histological preparations were carried out with the blood samples from the animals treated with chayotte during 15 days. Optical microscopy of red blood cells (RBC) showed important morphological alterations due to the treatment of the animals during 15 days with chayotte extract. The results could be justified by the metabolization of chayotte vegetable that could be capable to induce the generation of active metabolites with lesive properties in specific biological systems. The effects of the chayotte extract could also be due to a direct action of the compounds present in extract.

Aqueous extract of the medicinal plant Mentha crispa alters the biodistribution of the radiopharmaceutical sodium pertechnetate in Wistar rats

“…Passos et al (2000; have also demonstrated that dietary conditions can interfere with the biodistribution of radiobiocomplex. Several authors have also reported that, due to their pharmacological properties, some chemical compounds can alter the biodistribution of various radiobiocomplexes (Brito et al, 1998;Diré et al, 2003;Gomes et al, 2002;Diré et al, 2001;Grigoleit and Grigoleit, 2005;Hesslewood and Leung, 1994;Aguiar et al, 2002;Gomes et al, 2001;Mattos et al, 1999;Mattos et al, 2001).…”

“…It is well established that medicinal plants contain mixtures of various pharmacologically active compounds, and thus may have the potentiality to interfere with the labeling of radiobiocomplexes (Capriles et al, 2000;Amorim et al, 2003;Diré et al, 2004;Lima et al, 2003;Moreno et al, 2002;Moreno et al, 2005;Oliviera et al, 2002;Oliviera et al, 2003;Santos-Filho et al 2004) and/or with their biodistribution Capriles et al, 2000;Diré et al, 2003;Moreno et al, 2005;Diré et al, 2001).…”

Efeito de um extrato de Hipérico (Hypericum perforatum) na marcação in vitro de elementos sangüíneos com tecnécio-99m e na biodisponibilidade do radiofármaco pertecnetato de sódio em ratos Wistar

“…A distribuição, a fixação e a eliminação de radiofármacos em um organismo dependem de vários fatores, tais como o fluxo sanguíneo, o metabolismo tecidual e a ligação aos elementos sanguíneos 4,15 . Vários autores têm demonstrado que a biodisponibilidade de radiofármacos pode ser modificado por produtos naturais e sintéticos [6][7][8][9][10][11][12][13]22 .…”

“…. Essas hemácias marcadas também têm sido de importância em vários estudos clínicos e também experimentais de possível interesse para a pesquisa na medicina nuclear [4][5][6][7][8][9][10][11] . Essa marcação é baseada na capacidade de redução do cloreto estanoso (SnCl 2 ) que atua sobre o 99mTc, na forma de pertecnetato de sódio.…”

“…O radiofármaco pertecnetato de sódio é distribuído através dos líquidos vasculares e intersticiais e apresenta normalmente uma captação preferencial na tiróide, o estômago, trato intestinal, e glândulas salivares 14 . Vários fatores, como a terapia com drogas, a terapia com radiação, processos cirúrgicos, condições de dieta, além de doenças podem afetar a biodistribuição dos diferentes radiofármacos 9,[16][17][18][19] . Esses fatores levam a uma repetição do exame, resultando numa irradiação desnecessária ao paciente.…”