Age-Related Late Effects in Rat Thyroids After Internal 131I Exposure

Abstract

The Chernobyl nuclear accident left many questions in its wake. One of these questions was why children affected by the radioactive fallout seemed to have a higher incidence of thyroid cancer compared with adults in the same area. The purpose of this study was to compare proteomic changes in internally 131I irradiated rats of two age groups, one young and one adult. This was performed through analysis of fresh frozen thyroid tissue from a previous animal study where young and adult rats were exposed internally to various amounts of 131I. Analysis of the rats’ thyroid proteome was achieved through liquid chromatography tandem mass spectrometry and analysed with Welch’s t-test with Benjamini-Hochberg correction. Protein functional analysis and gene ontology (GO) term analysis were done with UniProt. Large variations in mainly the control group’s data made comparison at the group level difficult. One protein’s relative abundance, TRXR3, was found significantly changed in the young population at 0.5 kBq. TRXR3 is the rat equivalent to the TRXR3 found in humans and is a part of cellular oxidant detoxification and redox homeostasis. This would imply that oxidative stress had taken place, but the lack of other markers makes it difficult to draw a solid conclusion. Due to the lacking appearance at other doses, TRXR3 was not considered a good candidate biomarker for 131I radiation exposure or absorbed dose