A/J mouse genome sequencing, studies of germline mutations

To investigate the effects of chronic low-dose internal exposure to Cesium-137 radiation on successive generations and its impact on offspring, we administered Cesium-137-contained water (100 Bq/mL) to A/J mouse strains for more than 40 generations. Subsequently, we employed a comprehensive approach to assess individual effects within the exposed mouse population. Compared to the control group, the Cesium-137-exposed group exhibited a significant increase in DNA double-strand breaks and oxidative stress. However, no significant differences were observed between the two groups regarding chromosome aberration, micronuclei, and the whole genome sequence mutation analysis. Although no difference in carcinogenic rate was observed between the two groups, the rate of tumor growth was significantly suppressed in the Cesium-137 group. Cytokine levels in the Cesium-137 group showed a trend toward the activation of anti-tumor immunity, which likely contributed to the anti-tumor effect. For mice drinking water containing 100 Bq/mL (100,000 Bq/L) of cesium-137, no ill effects were observed on their offspring even after 25 generations of drinking.