腎クリアランスに関する研究 第II篇: 家兎腎のX線照射後に於ける腎変化と腎クリアランス

Abstract

1) Experimental radiation injury of the kidney was p r o duced in rabbit by external local irradiation to the site of kidney with various doses of x-ray. Changes of renal function were studied by means of renal clearance and gross and histological findings were observed following irradiation. 2) Th e experimental animals were divided in 5 groups according to the dose of x-ray, ranged from 1500r to 6000r, irradiated to the left kidney. The mortality rate increased with the dose irradiated. It was postulated that the radiation dosage in this manner might be better to not exceed 3000r to accomplish a prolonged observations for more than several months. 3) The values of GFR, RPF, RBF, FF and TmPAH were measured by means of renal clearances before and various stages after irradiation. The values of GFR, RPF and RBF immediately after the irradiation slightly and transiently rose above the pre-irradiated values, while a slight but rappid decrease in the value of TmPAH was observed in early stage of post-irradiation. However all of these values slowly decreased subsequently. In the value of FF, therefore, a slight and transient rise was seen after irradiation followed by gradual recovery. A 8 month observations could be perfomed as the longest one after the irrdiation. 4) The gross and histological changes of the irradiated kidney fairly concu r r ed with the changes of renal function measured by renal clearance. Grossly the irradiated kidney showed a transient hypertrophy and congestion with a subsequent tendency of atrophy which was iniciated around 2 month after the irradiation. Terminally atrophic nephrosclerosis was observed and the size of kidney became markedly smaller than control. Histologically, a marked degeneration of the renal tubules with a subsequent displacement of fibrous tissue and round cell infiltration were observed even in early period of post-irradiated stage. The alterations of glomerulus and vascular system were considerablly slower and milder than that of tubulus but secondary and progressive degenerations attributed to the tubular alterations were observed subsequently. Moreover, the larger radiation doses produced the earlier changes in the glomerulus and vascular system, while a similar change was seen in the non-irradiated kidney in terminal stage.