FUNDAMENTAL STUDY ON HOST IMMUNORESPONSE IN SUBRENAL CAPSULE ASSAY USING HUMAN UROGENITAL MALIGNANT NEOPLASMS TRANSPLANTABLE TO NUDE MICE

Abstract

The host immunoresponse of nude mice (BALB/c-nu/nu) and hetero mice (BALB/c-nu/+) in subrenal capsule assay were studied using bladder cancer (NM-B-1), prostatic cancer (PRO-1) and renal cancer (NM-R-3) transplantable to nude mice.
The implantation under the renal capsule in this study was carried out according to Bogden's basic method. After the sacrifice of these mice, the final tumor sizes were measured and the changes in tumor size were calculated on Day-4, Day-6 and Day-8 in hetero mice, and on Day-11 in nude mice. H-E and Azan stainings were also performed for histological analysis.
In hetero mice, changes in tumor size were most marked on Day-6 in NM-B-1 and NM-R-3, and on Day-8 in PRO-1. Histologically, in nude mice, all these tumor fragments (NM-B-1, PRO-1, NM-R-3) had many vivid cancer cells without host cell infiltrations. On the other hand, only minimal host cell infiltrations were observed and cancer cells appeared well preserved in these fragments of hetero mice on Day-4. But cancer cells were decreased and almost replaced by host cells with fibrous changes on Day-6. This tendency appeared remarkable on Day-8.
The present study has demonstrated that Day-6 subrenal capsule assay using immunocompetent mice have a problem of host immunoresponse which should be solved. There fore, it is more suitable to use athymic mice than immunocompetent mice as host animals in the subrenal capsule assay.