Non-targeted transcriptomic effects upon thyroid irradiation: similarity between in-field and out-of-field responses varies with tissue type
Artikel i vetenskaplig tidskrift, 2016
Non-targeted effects can induce responses in tissues that have not been exposed to ionizing radiation.
Despite their relevance for risk assessment, few studies have investigated these effects in vivo. In
particular, these effects have not been studied in context with thyroid exposure, which can occur e.g.
during irradiation of head and neck tumors. To determine the similarity between in-field and out-offield
responses in normal tissue, we used a partial body irradiation setup with female mice where the
thyroid region, the thorax and abdomen, or all three regions were irradiated. After 24h, transcriptional
regulation in the kidney cortex, kidney medulla, liver, lungs, spleen, and thyroid was analyzed using
microarray technology. Thyroid irradiation resulted in transcriptional regulation in the kidney medulla
and liver that resembled regulation upon direct exposure of these tissues regarding both strength of
response and associated biological function. The kidney cortex showed fewer similarities between the
setups, while the lungs and spleen showed little similarity between in-field and out-of-field responses.
Interestingly, effects were generally not found to be additive. Future studies are needed to identify
the molecular mechanisms that mediate these systemic effects, so that they may be used as targets to
minimize detrimental side effects in radiotherapy.