Table 5.

Relevant references related to lifespan, cancer endpoints, and non-cancer effects

Type of animal, strain/age	Irradiation details	Outcomes recorded, time post-exposure	Definitive findings	Reference
Wild-type animals
Mouse, A/J	γ-irradiation exposure over 3 weeks Doses: 60 and 600 mGy Dose rates 0.12 and 1.2 mGy/h	Lung cancer development at 46 weeks	60 mGy alone is protective, increased adenoma and carcinoma for combined 60 mGy–benzo[a]pyrene, 600 mGy combined less cancer	Bruce et al. (2012)
Mouse, C57BL/6 J	X-irradiation for 4 or 8 weeks Doses: 350, 700 and 1,400 mGy Dose rates 12.5 and 25 mGy every other day for group 1. Dose rates 12.5 and 25 mGy weekly for group 2	Diabetic nephropathy evaluation	Less kidney fibrosis, protection by 12.5 or 25 mGy for 8 weeks best Lower creatinine and connective tissue growth factor	Cheng et al. (2014) Cheng et al. (2018)
Dog, beagle	γ-irradiation for the entire duration of life Dose rates: LDR: 0.125; 0.31; 0.78; 1.6; 3.12 mGy/h HDR: 11; 15,6; 27 mGy/h	Myeloproliferative diseases, lifespan, tumours	Dose rate-dependent life shortening Hematopoietic failure for all dose rates except at 0.125 mGy/h	Fliedner et al. (2012);
Mouse, C57BL/6JJcl females mated with C3H/HeNJcl males, 6-week-old	γ-irradiation Doses of 360, 3,600, 7,200 mGy Dose rates: 0.8, 8.3 and 17 mGy/h	Pregnant mice exposure form day 0 to day 18 of gestation	Foetus size and foetal organ sizes, decreased in all groups at all doses and dose rates; some dose rate differences were noted with less impact at the lower dose rates	Gulay et al. (2018)
Drosophila melanogaster	Underground vs above ground environment (LNGS, Italy) Inside DUL: ~ 10–5 mGy/h	Life span, reproductive capacity, response to genotoxic stress (up to 3 months underground)	Maintenance in DUL environment prolongs the life span, limits the reproductive capacity of both male and female flies as well as the response to genotoxic stress Effects observed as early as after one generation time (10–15 days) and retained in a trans-generational manner (at least for 2 more generations)	Morciano et al. (2018a) Morciano et al. (2018b)
Lake whitefish (Coregonus clupeaformis)	Underground vs above ground environment (SNOLAB, Canada) Inside DUL: ~ 10–6 mGy/h	Timing of hatch, survival, increase in body length and body weight (up to about 5 months underground)	Incubating embryos within SNOLAB can have a subtle yet significant effect on embryonic growth and development. (significant increase in body length and body weight of up to 10% observed in embryos reared underground)	Pirkkanen et al. (2020)
Mouse, B6C3F1	γ-irradiation exposure for 400 days Doses 8,000, 400 and 20 mGy Dose rates: 0.002; 0.05 and 0.8 mGy/h	Lifespan, neoplasia	Body weight increase for 0.05 and 0.08 mGy/h Increase in the number of multiple primary neoplasms per mouse after 0.8 mGy/h (total dose 8 Gy)	Tanaka et al. (2007) Braga-Tanaka et al. (2018b)
Caenorhabditis elegans	Underground vs above ground environment (WIPP, USA) Inside DUL: ~ 10–5 mGy/h	Rate of larvae growth; egg layering, gene expression (1 week underground or 8 months underground)	Faster rates of larval growth, a faster rate of early egg laying, and more than 100 genes were differentially regulated, compared to normal background radiation levels	Van Voorhies et al. (2020)
Mouse, BCF1	γ-irradiation exposure for 400 days Doses: 20, 400 or 2000 mGy Dose rates: 2 × 10–3, 4.6 × 10–2, 0.87 mGy/h	Tumour incidence	Similar incidence for similar doses vs. Tanaka; fractionated radiation decreases incidence for any dose	Zander et al. (2020)
Transgenic animals
Mouse, ApoE−/− male on C57BL/6 J; 8 weeks	γ-irradiation Doses: 69, 161 mGy Dose rates: 1.2 × 10–2 and 2.8 × 10–2 mGy/h	Pathology of atherosclerosis	Macrophages and gene expression show adaptive response Cytokines (IL-4, -10, -13 and -18), catalase, SODs, and CTAT1 upregulated	Ebrahimian et al. (2018a)
Mouse, MRL-lpr/lpr female, 5 weeks old	γ-irradiation Dose rates: 0.35 and 1.2 mGy/h	Life expectancy	Best improvements in life expectancy with 1.2 mGy/h at 5 weeks, some with 0.35 mGy/h	Ina and Sakai (2005)
Mouse, ApoE−/− on C57BL/6 J; 8-week-old	γ-irradiation Doses: 25–2000 mGy Dose rates: 60 mGy/h and 9 × 103 mGy/h	Heart pathology and aortic atherosclerosis	Adaptive response at doses up to 0.5 Gy; increased capillary density, evident at low- and high-dose rates Decreased inflammatory vascular markers; changes of collagen IV and Thy-1 tissue levels	Mathias et al. (2015)
Mouse, ApoE−/− on C57BL/6 J; irradiated at 2 or 8 months of age	γ-irradiation Doses: 25, 50, 100 and 500 mGy Dose rates: 60 mGy/h and 9 × 103 mGy/h	Pathology of aortic atherosclerosis exposure at 2 months and examined at 3 or 6 months later; exposure at 8 months and examined at 2 or 4 months later	Disease slowed down by 25 or 50 mGy delivered at 60 mGy/h	Mitchel et al. (2011)
Female mouse C57BL/6 J ApoE−/− Trp53+/− mice irradiated at 2 or 7 months of age	γ-irradiation Doses: 25, 50, 100 and 500 mGy Dose rates: 60 mGy/h and 9 × 103 mGy/h	Aortic root lesions Exposure at 2 months and examined at 3 or 6 months later; exposure at 7 months and examined at 2 or 4 months later	When exposed at early stage, decrease of lesion progression after doses as low as 25 mGy either after the high or the low-dose rate, Detrimental effect for both dose rates when exposed at later stage	Mitchel et al. (2013)