Radiation damage in rat kidney microvasculature.

Scanning electron microscopy (SEM) combined with a specialized polymer injection casting technique permits the analysis of radiation induced damage in rat kidney glomeruli. A lead shielding device is constructed to enable the irradiation of the living rat left kidney, while the remainder of the animal is shielded from the dose, the right kidney serves as a control. The source of radiation is 137Cs which produces 0.66 MeV gamma-rays to achieve a kidney dose of 100 rad and 5000 rad in these experiments. Radiation damage to kidney glomeruli is assessed at intervals of 0, 1, 3 and 7 days post-irradiation at the two dose levels. It is found that radiation damage to kidney glomeruli is expressed morphologically at 7 days post-irradiation at the 100 rad dose level, while glomerular damage is apparent as early as 3 days post-irradiation at the 5000 rad dose level. Moreover, by 7 days post-irradiation with a 5000 rad dose, the kidney glomerulus thoroughly degenerates to a leaky fused mass of vessels. From a morphological viewpoint, kidney glomeruli are significantly more sensitive to radiation than surrounding vasculature. The methods developed here for assessment of radiation damage are highly repeatable and could serve as a standard technique in radiobiology.