Intraperitoneal transplantation of ascitic cancer cells from a 7,12-dimethylbenz[a]anthracene (DMBA)-induced ovarian cancer.

Intra-abdominal implantation of 7,12 dimethylbenz[a]anthracene (DMBA)-induced rat ovarian cancer tissue produces intraperitoneal carcinomatosis with a high incidence. The peritoneal carcinoma produces malignant ascites in 62% of the donor rats. The ascites is bloody in appearance and includes an average of 1.2 x 10(6) cancer cells/ml. To observe the transplantability of the ascites, 0.1 ml of a condensed ascites with 4 x 10(6) cancer cells was injected into the abdominal cavity of 118 infant rats that were 2 to 4 days old. In 103 rats (87%), the ascitic cells were successfully transplanted. Twelve rats were sacrificed each week from the 2nd to the 6th week following the inoculation. The omentum was the first site at which the metastastic tumor appeared following the inoculation. Then the tumor disseminated throughout the intraperitoneal cavity and produced bloody ascites by the 3rd week. Eighty-four rats were observed to determine the survival, and it was 34 +/- 10 days. Cytologically the ascites had clusters of tumor cells resembling bunches of grapes. The ultrastructure of the ascitic cells was globular shaped with many microvilli and epithelial attachments. The histology of the developed tumor was that of an adenocarcinoma. Due to morphological similarity with advanced human ovarian cancer and the high reproducibility, this experimental system could be a feasible model for human ovarian cancer, especially the type which produces malignant ascites.