Objective:Tostudythe effects ofsimulated carbon dioxide pneumoperiton eumenvironment on cell proliferation of human renal carcinoma 786-O cells in vitro.Methods:The renal carcinoma 786-O cells were exposed to simulated CO2 pneumoperitoneum environment for different time periods(2 h or 4 h)under the pressure of 14 mmHg and those cultured in normal experimental condition as control

then proliferation viability of 786-O cells was observed by MTT assay close behind the exposure;cell cycle and apoptotic rate were detected by flow cytometry

the protein expression of PCNA and Survivin were examined by immunocytochemistry 48 h after exposure respectively.Results:Compared with the control group

Both of the treated groups showed cell proliferation was significantly increased (P<0.05)

and the increasing had a linear relationship with exposure time(R2=1

P<0.01);The proliferative index(PI)showed significant difference from that of control group(P<0.01);In cell cycle

the percentages of S-phase and G2/M phase were significantly higher in treated groups than those in control group(P<0.05);PCNA protein was found to be significantly upregulated in treated groups (P<0.05).The apoptotic rates were significantlydecreased(P<0.01)

andthe decreasinghadalinearrelationshipwithexposure time;the expressions of Survivin

which related with apoptosis

were significantly increased(P<0.01).Conclusion:Carbon dioxide could promote the proliferation of human renal carcinoma 786-O cells

and the proliferation would be sped up with the prolongation of exposure time.