In vitro evaluation of a simulated pneumoperitoneum environment using carbon dioxide on canine transitional cell carcinoma.

ABSTRACT

OBJECTIVE: To assess the impact of a simulated CO2 pneumoperitoneum environment on the viability and proliferation of canine transitional cell carcinoma (TCC) cells in vitro. STUDY DESIGN: In vitro study. METHODS: A control Madin-Darby canine kidney (MDCK) cell line and 3 canine TCC cell lines were exposed to 100% CO2 at pressure of 0, 5, 10, or 15 mmHg for 2 hours by using an airtight chamber and a mechanical insufflator at 37°C. Culture media pH was measured. Viability and proliferation were assessed by using a resazurin assay and trypan blue dye, respectively. RESULTS: The pH in the media significantly decreased immediately after CO2 exposure but returned to normal within 1 hour. The viability of the cell lines was variably affected at the evaluated pressures. Insufflation pressure of 10 mmHg resulted in significantly decreased cell viability compared with control. The impact of 15 mmHg CO2 was comparable to 0 mmHg and control. CO2 insufflation pressure had no significant effects on proliferation up to 7 days postexposure. Conclusion/Clinical significance: A positive pressure CO2 environment significantly decreased the viability of TCC and MDCK cells under specific conditions without influencing their proliferation up to 7 days postexposure. Investigating these effects in clinical patients undergoing CO2 laparoscopy is essential to assess for port site metastasis or peritoneal carcinomatosis in order to translate these in vitro results to clinical recommendations.