Evaluation of the cytogenetic effects of (131)I preceded by recombinant human thyrotropin (rhTSH) in peripheral lymphocytes of Wistar rats.
The present study was carried out to investigate the cytogenetic effects of therapeutic exposure to radioiodine preceded by rhTSH in an animal model. Three groups of Wistar rats (n = 6) were used: one group was treated only with (131)I (11.1 MBq/animal); the other two groups received rhTSH (1.2 mug/rat of either Thyrogen or rhTSH-IPEN, respectively) 24 h before administration of radioiodine. The percentage of lymphocytes with chromosome aberrations and the average number of aberrations and of dicentrics per cell were determined on blood samples collected 24 h, 7 and 30 days after administration of (131)I. The data show that the treatment with radioiodine alone or associated with rhTSH resulted in a greater quantity of chromosome alterations in relation to basal values after 24 h, with a gradual decline after 7 and 30 days of treatment. An increase in chromosome alterations was also seen after rhTSH treatment alone. Neither of the treatments, i.e., with (131)I alone or associated with hormone, resulted in an aneugenic effect or influenced the kinetics of cellular proliferation in rat blood lymphocytes. There was no significant difference between the cytogenetic effects of Thyrogen and rhTSH-IPEN treatment. These data suggest that the treatment with radioiodine, associated or not with rhTSH, affects to a limited extent a relatively small number of cells although the occurrence of late stochastic effects could not be discarded.
da Silva
Márcia Augusta
MA
Centro de Biotecnologia, Instituto de Pesquisas Energéticas e Nucleares, IPEN-CNEN/SP, Cidade Universitária, Av. Prof. Lineu Prestes, 2242, Caixa Postal 11049, CEP 05508-900 São Paulo, Brazil.
Calil Cury Guimarães
Maria Inês
MI
Yoriyaz
Hélio
H
Carvalho Pinto Ribela
Maria Teresa
MT
Buchpiguel
Carlos Alberto
CA
Bartolini
Paolo
P
Okazaki
Kayo
K
D000818:Animals; D002478:Cells, Cultured; D002869:Chromosome Aberrations / Q000187:drug effects* / Q000528:radiation effects*; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes / Q000008:administration & dosage*; D008214:Lymphocytes / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D011829:Radiation Dosage; D051381:Rats; D017208:Rats, Wistar; D013972:Thyrotropin / Q000008:administration & dosage* / Q000235:genetics
D007457:Iodine Radioisotopes; D013972:Thyrotropin