[Evaluation of cancer chemotherapy using rat ovarian cancer induced by DMBA--observation of histologic effects by light and transmission electron microscopy, and changes in vascular system after cis-DDP treatment].

Cis-DDP was administered to 28 rats with ovarian cancer induced by DMBA. Four to five weeks after the treatment, they were sacrificed and the effects of the anticancer agent were evaluated in regard to relative tumor size before and after the treatment, and histologic effects were investigated by light and electron microscopy. Microangiography was also performed to study vascular changes in the tumor. 1. In seven cases, a significant reduction in the tumor size was found after the cis-DDP treatment. 2. Various degrees of histologic effects were observed in either the tumor increased group or the decreased group, and even in the latter group an excellent histologic effect was recognizable. 3. A proliferation of connective tissues presumably played a significant role in the increase of tumor size observed after chemotherapeutic treatment. 4. On transmission electron microscopic observation, it appeared that cell death was indicated by pyknotic nuclei and destruction of cell organella. A reduction in the number of chromatin and ribosomes indicated a decrease in cell activity. 5. Multi-nuclei-giant cells appeared among the connective tissue in one case. 6. On microangiography, the DMBA induced tumor generally showed hypovascularity, and cis-DDP induced reduction in the number of blood vessels.