Late Effects of Low-Dose Radiation on the Bone Marrow, Lung, and Testis Collected From the Same Exposed BALB/cJ Mice

Abstract

We used 3 biological metrics highly relevant to health risks, that is, cell death, inflammation, and global DNA methylation, to determine the late effects of low doses (0.05 or 0.1 Gy) of 137Cs γ rays on the bone marrow, lung, and testis collected at 6 months post-irradiation from the same exposed BALB/cJ mouse. This integrative approach has not been used for such a purpose. Mice exposed to 0 or 1 Gy of radiation served as a sham or positive control group, respectively. The results could deliver information for better health risk assessment across tissues, including better scientific basis for radiation protection and clinical application. We found no changes in the levels of all studied biological metrics (except a significant increase in the levels of an anti-inflammatory cytokine, ie, interleukin 10) in tissues of 0.05-Gy exposed mice, when compared to those in sham controls. In contrast, significantly increased levels of cell death and inflammation, including a significant loss of global 5-hydroxymethylcytosine, were found in all tissues of the same mice exposed to 0.1 or 1.0 Gy. Our data demonstrated not only no harm but also hormesis in the 0.05-Gy exposed mice. However, the hormetic effect appears to be dependent on biological metrics and tissue.

Radiation-induced cardiovascular disease: an overlooked role for DNA methylation?

“…Previous research has linked altered DNA methylation to the development of many diseases including CVD [11,12]. Conversely, ionizing radiation has been shown to cause DNA methylation alterations both in vitro and in vivo [13][14][15][16]. Considering the common occurrence of DNA methylation alterations in CVD and after ionizing radiation exposure, we suggest a previously unaddressed involvement of DNA methylation in radiation-induced CVD.…”

“…This is because of the varying aims of these studies which range from the investigation of radiation-induced carcinogenesis, radiation-induced genomic instability and bystander effects [13][14][15]95,101,102,109,110] to cellular responses to radiation and radiosensitivity [100,103,104,108]. In addition, some studies addressed the difference between the effects of IR on somatic and germinal tissues [16].…”

Organ-Specific Effects of Low Dose Radiation Exposure: A Comprehensive Review

“…Although many studies opposed it through showing LDR (0.1 and 0.2 Gy) reportedly promoted cell death, inflammation, ROS generation (lipid oxidation), and DNA damage (5-hydroxymethylcytosine); and activated damage responses (p53, p38, p21, ERK1/2, NF-κB, TGF-β, etc.) in the lung, these studies unanimously agreed that certain irradiation conditions resulted in less severe changes in lung than that in the liver and the spleen ( Sypin et al, 2003 ; Avti et al, 2005 ; Lee et al, 2006 ; Kim et al, 2007 , 2015 ; Hong et al, 2014 ; Jangiam et al, 2018 ). Moreover, the protective roles of LDR in the lung have been demonstrated in various stress models.…”

“…Many studies have shown that the lung ranks among the organs that are most resistant to LDR damage. LDR (0.05–0.6 Gy) did not induce significant biological damage in the lung ( Sypin et al, 2003 ; Kim et al, 2007 ; Jangiam et al, 2018 ; Puukila et al, 2019 ). Although many studies opposed it through showing LDR (0.1 and 0.2 Gy) reportedly promoted cell death, inflammation, ROS generation (lipid oxidation), and DNA damage (5-hydroxymethylcytosine); and activated damage responses (p53, p38, p21, ERK1/2, NF-κB, TGF-β, etc.)…”

Spectroscopic Studies of in Vitro Exposure to Low-Dose Gamma Rays from 137Cs Radioactivity on Some Human Blood Components (Plasma and Red Blood Cells)

“…The authors found that the number of cell death, DNA damage, and in ammation response did not signi cantly change in bone marrow, lungs, and testis of mice that were exposed to 0.05 Gy of 137 Cs gamma rays, when compared to a sham control. In contrast, signi cant changes in the number of cell death, DNA damage, and in ammation responses were shown in bone marrow, lungs, and testis of mice that had been exposed to 0.1 and 1.0 Gy of 137 Cs gamma rays [24]. It should be noted that there was a difference in biological response to 0.05 Gy of gamma rays, when compared to 0.1 or 1.0 Gy exposure.…”