Age-related long-term response in rat thyroid tissue and plasma after internal low dose exposure to 131I

Abstract

Abstract131I is used clinically for therapy, and may be released during nuclear accidents. After the Chernobyl accident papillary thyroid carcinoma incidence increased in children, but not adults. The aims of this study were to compare 131I irradiation-dependent differences in RNA and protein expression in the thyroid and plasma of young and adult rats, and identify potential age-dependent biomarkers for 131I exposure. Twelve young (5 weeks) and twelve adult Sprague Dawley rats (17 weeks) were i.v. injected with 50 kBq 131I (absorbed dose to thyroid = 0.1 Gy), and sixteen unexposed age-matched rats were used as controls. The rats were killed 3–9 months after administration. Microarray analysis was performed using RNA from thyroid samples, while LC–MS/MS analysis was performed on proteins extracted from thyroid tissue and plasma. Canonical pathways, biological functions and upstream regulators were analysed for the identified transcripts and proteins. Distinct age-dependent differences in gene and protein expression were observed. Novel biomarkers for thyroid 131I exposure were identified: (PTH), age-dependent dose response (CA1, FTL1, PVALB (youngsters) and HSPB6 (adults)), thyroid function (Vegfb (adults)). Further validation using clinical samples are needed to explore the role of the identified biomarkers.

Late Age- and Dose-Related Effects on the Proteome of Thyroid Tissue in Rats after ¹³¹I Exposure

“…When comparing our present findings with those from our previous studies on similar types of rats at earlier time points (24 hours, and 3, 6, and 9 months), none of the previously suggested protein biomarkers were seen in the present study [20,43,44]. However, the thyroid hormone metabolism signalling pathway, has previously been seen using the IPA software at 24 h post irradiation for similar dose levels [17].…”

Late Age- and Dose-Related Effects on the Proteome of Thyroid Tissue in Rats after 131I Exposure

“…When comparing our present findings with those from our previous studies on similar types of rats at earlier time points (24 h, and 3, 6, and 9 months), none of the previously suggested protein biomarkers were seen in the present study [20,43,44]. However, the thyroid hormone metabolism signaling pathway, has previously been seen using the IPA software at 24 h postirradiation for similar dose levels [17].…”