Description of two new human ovarian carcinoma models in nude rats suitable for laparoscopic experimentation

Background: Experimental laparoscopic trials require relevant models of ovarian carcinomatosis. Methods: Female nude rats were inoculated intraperitoneally either with the IGR-OV1 or the NIH:OVCAR-3 human adenocarcinoma cell lines. Serial clinical checks and sacrifices were used to evaluate the rates of tumor take, survival, and patterns of tumor spread. Finally, laparoscopies with various pneumoperitoneum pressures were performed to verify the "surgical" relevancy of out models. The learning curve was measured. Results: The best results were obtained when twenty-seven 10(6) IGR-OV1 cells and thirty-six 10(6) NIH:OVCAR-3 cells were injected in 28-day-old rats. The IGR-OV1 model provided a mean survival of 17.8 days (range, 13-22 days), with a high take rate (94%). The NIH:OVCAR-3 model resulted in a longer mean survival (59 days; range, 49-77) and also a high take rate (83%). The two models differed in their patterns of tumor spread: solid bulky omental metastasis having a diffuse microscopic peritoneal carcinomatosis with the IGR-OV1 line (the weight of the omental cake correlated significantly with the stage of development) and diffuse macroscopic peritoneal carcinomatosis having no large solid tumor, but visceral and paraaortic metastases, with the NIH:OVCAR-3 line. In both models, CA125 was high. Anesthesia could be performed and repeated in healthy and tumor-bearing rats. Laparoscopy was feasible, with pneumoperitoneum pressures as high as 8 mmHg lasting 1 h. Laparoscopy provided a reliable evaluation of the tumor spread into the peritoneal cavity. The plateau of the learning curve was soon obtained for take rate and survival after laparoscopy. Conclusion: We report two new human ovarian carcinoma xenografts in nude rats suitable for laparoscopy. The IGR-OV1 model mimics an advanced stage of the disease, and the NIH:OVCAR-3 model presents an earlier stage. These two models appear useful for experiments involving laparoscopy.