A STUDY OF THE INTERACTION OF METHYLMERCURIC CHLORIDE AND GAMMA IRRADIATION ON PEROXISOMES AND LYSOSOMES.

摘要

The first part of the investigation reported in this dissertation was a histochemical study conducted to determine the effect of several agents on the number of P-L organelles in the nucleus arcuatus of the brain and the number of peroxisomes and lysosomes in the nucleus arcuatus of rat brain, liver and kidney. Serial section, 7 micrometers thick, of the brain tissues were stained by Bargmann's modified method to show P-L organelles. Other sections of the brain, liver and kidney were incubated in DAB medium and stained with lead citrate to show peroxisomes while other separate sections were incubated in CMP and stained in lead citrate to show lysosomal organelles. A counterstain of haematoxylin was also used to help differentiate peroxisomes from lysosomes in tissue sections treated to show both organelles.; Histochemical analyses and morphological observations revealed a significantly greater total number of the three organelles in all three tissues examined in animals treated with distilled water than in any of the other treatments. The largest decrease in the number of organelles was in animals treated with MMC. The possible proliferation of P-L organelles and the high number of these organelles in the nucleus arcuatus suggested by other workers was not observed. A reduction in the toxic effects of MMC produced by whole body gamma radiation was demonstrated. In animals treated with MMC, histological examination of the tissues showed a similar pattern of effect in all three: rupture of organellar membrane and total destruction of some organelles. The same effect was observed, but to a lesser extent, in the MMC and gamma irradiation co-insult group.; The second part of the investigation was a lethality study designed to explore the hypothesis that hydrogen peroxide pretreatment provides protection against gamma irradiation.; A total of 60 mature male rats were used in the study. Animals were divided randomly into five groups. The experimental Groups I, II, and III, received five doses of 1.0, 1.4, or 1.8 ml of 1.5% hydrogen peroxide, respectively. Group IV received 5 doses of distilled water and all received 775 R gamma irradiation. Group V, and VI received five doses of 1.8 ml hydrogen peroxide and 1.8 ml distilled water, respectively and sham radiations. Deaths were recorded during a 30 day period. Results revealed 50% - 80% mortality among irradiated rats pretreated with hydrogen peroxide, while 60% mortality was obtained in irradiated animals pretreated with distilled water. Deaths occurred earlier in the hydrogen peroxide than in the distilled water treated animals. Therefore, it was concluded that hydrogen peroxide pretreatment did not afford protection against 775 R whole body ('60)Co gamma irradiation under the conditions of this study.