Early alterations in spinal marrow, liver and intestine of rats after total-body irradiation

Rats of the same Wistar-line were collectively exposed to total-body irradiation with 250, 500 or 1000 rd by a 60Co-source. Supravitally perfusion-fixated preparations of spine-marrow, liver and small intestine were histologically examined 5 hours, 4 and 12 weeks after irradiation (resp. 3 days following 1000 rd.). According to Rubin, in the case of liver and intestine no prognostic statements are possible regarding the extent of late alterations, in view of the early effects; for the spinal marrow early effects are not to be expected. By means of histological analyses in these organs are compared the early reactions and their repair, which have prognostic importance with respect to the 'latent chronic injury' to be expected in the tissues. Despite the uniform action of the 60Co-radiation upon all organs, there resulted organ-specific alterations. Particularities of tissue architectonics as well as a differing 'regenerative potency' very likely account for the early radiation response of the organs investigated. In the spinal marrow an intracellular glial edema in addition to the formation of extensive perivascular gaps interferes with the nutritive supply of the nerve cells. In liver and intestine, on the other hand, an acute interstitial edema is quickly resorbed (lymphatic drainage), here the pathological changes in the vascular system impair the supply of the tissues. Liver and intestine suffer the greater total damage with losses of function, as their parenchyma cells are more radiosensitive than the nerve cells. The 'latent chronic injury' has to be interpreted as an injury to functional and structural metabolism by repair processes in irradiated cells. (orig.)