Figure 1.
Experimental design and radiation survival.
A. Embryos were irradiated with 1 GeV/u 56Fe ions or with γ-rays, reared, and scored for survival as described in Materials and Methods. At the indicated times, male fish from each dose group were sacrificed and the livers analyzed. B, C. Kaplan-Meier survival curves for fish exposed as embryos to indicated doses and types of radiation.
Figure 2.
Age and dose-dependent accumulation of 4-hydroxynonenal in liver tissue.
Liver sections were stained with anti-4-hydroxy-2-nonenal (4-HNE) and hematoxylin counterstain as described in Materials and Methods. A. Bright-field images showing weak, moderate, or intense anti-4-HNE immunohistochemical staining. Scale bars = 20 µm. B. Nuance renderings of images from Panel A (yellow, 4-HNE; blue, cell nuclei). C. Quantification of 4-HNE staining based on Nuance analysis. Box plot shows mean and interquartile ranges. Color denotes dose group. Values are normalized to 0 Gy, 250 day group. D. Plot showing correlation between actual and predicted natural logarithm (ln)-transformed 4-HNE values for HZE cohort. Predicted values are based on regression model incorporating age, dose, and dose-squared parameters. Each symbol represents one individual. Shape denotes age group; color denotes dose group using same values as in Panel B. E. Plot showing predicted 4-HNE values as a function of age and HZE dose. F, G. Same as Panels D, E for γ-ray cohorts. Regression model incorporates an age parameter only; dose parameters were non-significant.
Table 1.
Age and dose dependence for 4-HNE.
Figure 3.
Age and dose-dependent decline in PPARGC1A mRNA in liver tissue.
A. Quantification of PPARGC1A mRNA. Box plot shows mean and interquartile ranges. Color denotes dose group. Values are normalized to 0 Gy, 250 day group. B. Plot showing correlation between actual and predicted PPARGC1A values. Each symbol represents one individual. Shape denotes age group, color denotes dose group using same values as in Panel A. Plot showing predicted PPARGC1A values as a function of age and HZE dose. Note that vertical axis shows relative mRNA amounts (i.e., back-transformed from ΔΔCt values). D, E, same as Panels B, C for γ-ray cohorts.
Table 2.
Age and dose dependence for expression of PPARGC1A mRNA.
Figure 4.
Analysis of mitochondrial ultrastructure.
Panels A–C show relatively normal mitochondria (triangles) from a non-irradiated individual and two examples of enlarged and elongate mitochondria (*) from HZE-exposed groups. D. Mitochondrial area as a function of HZE dose (left panel). Percent of elongated mitochondria as a function of dose (right panel).
Figure 5.
Necrotic cysts in livers of radiation-exposed individuals.
A. Representative hematoxylin and eosin stained sections. The left panel shows normal liver, and the right panel shows a necrotic cyst. Insets show regions of each section at higher magnification. Scale bars are 20 µm. B. Stacked column graph showing the incidence of necrotic cysts, classified according to the percentage area of the liver that was affected. C. Pooled data showing incidence of necrotic cysts at different doses of HZE particle radiation. Lesions of different severity were combined and classified as abnormal. Different age groups were also combined. P values are shown based on ordinal logistic regression. D. Stacked column graph, as in Panel B but for γ-ray exposed groups. E. Pooled data showing incidence of necrotic cysts at different doses of γ-rays.