Evaluation of the p53 tumor suppressor gene mutation in normal rat salivary gland tissue after radioiodine application: an experimental study.
In this experimental study, investigators explored p53 tumor suppressor gene mutation induced by low and high doses of iodine-131 sodium iodide (I-131) in salivary gland tissue in rats. Group 1 consisted of 10 rats; low and high I-131 doses were applied at a 1-wk interval. First,low doses of I-131 were injected. (The net injected dose was 47.5-/+9.2 microCi.) After 1 wk, high doses of I-131 were also injected. (The net injected dose was 1007.2-/+53 microCi.) Group 2 consisted of 5 rats, and only a low I-131 dose was applied. (The net injected dose was 52.7-/+5.5 microCi.) The Control Group consisted of 5 rats that did not receive I-131. Thyroidal I-131 uptakes were calculated for Groups 1 and 2 with the use of a gamma camera after 24 h of injections. Immediately after uptake was calculated, salivary glands were resected in all groups and DNA was extracted for genotyping. Genomic DNA of the p53 gene exon 5 was examined by polymerase chain reaction single-strand conformational polymorphism. In Group 1, thyroidal I-131 uptakes were calculated as 12.45%-/+4.14% and 9.66%-/+6.73% after low-dose and high-dose I-131 applications, respectively. In Group 2, thyroidal I-131 uptake was calculated as 13.12%-/+3.04%. In Group 1, p53 gene abnormality was seen in the salivary gland of only 1 of the rats. Double- and single-strand gene profiles showed that both alleles of this rat have a mutated single-strand conformational polymorphism profile of point mutation in the p53 gene exon 5. This rat received the highest low dose and the second highest total dose of I-131; its thyroidal uptakes were the second highest. In the other rats in Group 1, and in Group 2 and the Control Group, p53 gene abnormalities were not observed. In Groups 1 and 2, a significant relationship could not be discerned between thyroidal uptake of I-131 and p53 gene mutation in the salivary gland. No significant relationship was observed between thyroidal uptake alterations and p53 gene mutations in salivary glands in Group 1. A point mutation in the p53 gene exon 5 that was seen in only 1 of the rats in Group 1 seems related to the high-dose application of I-131, although coincidental occurrences could not be excluded. We believe that this topic is open to additional in vivo studies.
Turgut
Bulent
B
Department of Nuclear Medicine, Cumhuriyet University School of Medicine, Sivas, Turkey.
Ozdemir
Ozturk
O
Erselcan
Taner
T
D000818:Animals; D004305:Dose-Response Relationship, Drug; D007457:Iodine Radioisotopes / Q000009:adverse effects; D008297:Male; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D018807:Polymorphism, Single-Stranded Conformational; D019275:Radiopharmaceuticals / Q000009:adverse effects* / Q000493:pharmacokinetics; D051381:Rats; D017208:Rats, Wistar; D012469:Salivary Glands / Q000378:metabolism / Q000528:radiation effects*; D012974:Sodium Iodide / Q000009:adverse effects*; D013961:Thyroid Gland / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000235:genetics*
D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D016159:Tumor Suppressor Protein p53; D012974:Sodium Iodide