1Universidade do Estado do Rio de Janeiro, Instituto de Biologia Roberto Alcantara Gomes, Departamentos de Biofisica e Biometria, RJ, Brazil.
2Universidade do Estado do Rio de Janeiro, Faculdade de Ciâncias Médicas, Departamentos de Patologia Geral, RJ, Brazil.
3Instituto Nacional do Câncer, Coordenadoria de Pesquisa, Rio de Janeiro, RJ, Brazil
*Correspondence to: G.F. Diré, Universidade do Estado do Rio de Janeiro, Instituto de Biologia Roberto Alcantara Gomes, Departamentos de Biofisica e Biometria. Av. 28 de setembro, 87, Rio de Janeiro, RJ 20551-030, Brazil. Fax: +552122543532/+552125876432 e-mail: gdire@hotmail.com.
Natural products have been widely used by human beings. However, sometimes the biological effects of these products are not fully known. Many natural medicines may contain potentially toxic ingredients and contaminants such as heavy metals. Some studies suggested that diabetes would be related to an oxidative stress which may be related to the disturbed gene expression, essential in the control of the ontogenetic processes. Red blood cells (RBC) and plasma proteins labeled with technetium-99m (99mTc) have several clinical applications and it has been reported that some natural products are capable of reducing the efficiency of this radiolabeling. The aim of this work was to assess the effect of an extract of Sechium edule on the labeling of blood elements with 99mTc. A freshly extract of Sechium edule was administered to Wistar rats for 7 days. After that, samples (0.5ml) of blood were incubated with stannous chloride (SnCl2) and 99mTc. The blood was centrifuged and plasma (P) and RBC were isolated. P and RBC were also precipitated with trichloroacetic acid and soluble (S) and insoluble (I) fractions (F) were determined. The radioactivity (ATI%) was rated in RBC, IF-P and IF-C in a gamma well counter. A decrease was observed in the uptake of %ATI by the blood cells in the diabetic group treated with chayotte (89.96 ± 5.16) in comparison to the diabetic group (97.16 ± 1.26). Related to the %ATI binding in the IF-P a decrease was noticed in the efficiency of radiolabeling in the diabetic group (from 80.22 ± 5.50 to 71.16 ± 1.97) and in the diabetic group treated with the extract (from 80.22 ± 5.50 to 70.87 ± 4.10). A decrease of the %ATI binding to the IF-C was observed in the goup treated with chayotte extract (from 91.08 ± 4.10 to 67.26 ± 2.20), in the diabetic group (from 91.08 ± 4.10 to 71.26 ± 2.46) and in the diabetic group treated with chayotte (from 91.08 ± 4.10 to 71.51 ± 3.38). In the light of the results the referred extract has shown an oxidant action. We suggest that the referred extract may induce the generation of active metabolites with exhibiting action on the labeling process probably by acting on the cell membrane and on the binding site proteins due to oxidative stress occurring in diabetes.
chayotte, red blood cells, plasma proteins, diabetes, technetium-99m
