[Application of renal subcapsular assay to rat malignant brain tumor]

As a rapid screening method for testing chemotherapeutic agents against human tumor explants, renal subcapsular assay has been established by Bogden et al (1978). The authors investigated the effectiveness of the technique of Bogden for rat glioma. Preselected 1 mm3 fragments of viable tumor tissue of rat (CDF) were implanted under the renal capsule of normal immunocompetent rats. Then initial and final tumor sizes (formula; see text) were measured in situ with an oculometer inserted into a surgical microscope, and evaluated the changes of tumor sizes. The experiments were divided into three groups. The first group was that tumor pieces of rat (CDF) were implanted under the renal capsule of the syngenetic rats (CDF). Non-irradiated and preirradiated (400 rad) heterogenetic rats (Wistar) were used as the second and third groups. The explanted tumor pieces grew rapidly in the first group (syngenetic rats). On the other hand, poor growth of the second group (non-irradiated heterogenetic rats) was seen within 7 days after implantation, and rejected completely until 15 days after implantation. Explanted tumor pieces in the third group (pre-irradiated heterogenetic rats), however, grew enough big, though the change of tumor sizes was less than that of the first group. Histological examination was also performed. In the first and third group, proliferation of glioma cells was remarkable under the renal capsule, and neovascularization in the explanted tumor tissue was provided from the capsule, first, and then parenchym of the kidney. Even necrosis and hemorrhage were seen in the tumor tissue 15 days after implantation.(ABSTRACT TRUNCATED AT 250 WORDS)