Abstract
The growth and the survival after transplantation of tumor cells were compared between mice kept in wire-mesh cages (16×28×12cm) (Fig.1) and mice kept in polycarbonate cages with wood shavings (18×27×13cm) (Fig.2) . ICR-JCL and ddY-SLC mice of both sexes were kept separately 5 each in a cage, maintained in an airconditioned animal room (26±0.5°C and 60-70% in relative humidity) artificially illuminated (12h light from 8: 00 AM to 8: 00PM), and they were provided with commercial diet (CE-2 : CLEA Japan Inc., Tokyo) and wateras libitum. Individual body weight was measured every 10 days during 30-140 days of age. Thereafter, about 107of living cells of asci tes sarcoma 180 and Ehrlich ascites carcinoma were transplanted subcutaneously and survival days were checked. There were little differences in the growthexcept male ddY-SLC mice of which body weights after 90 days of age were significantly heavier in wire-mesh cages than in polycarbonate cages (Figs. 3 and 4) . The survival days after transplantation of tumor cells were not different between mice in wire-mesh cages and those in polycarbonate cages in either sex of both ICR and ddY mice (Table 1) . These results indicate that a wire-mesh cage is useful without disadvantages for maintenance of mice, especially in automatic or labor saving systems.
