Effect Of Carbon Dioxide On Invasion Of Hepatomcarcinoma Cells In Vitro

Objective: To observe the effect of pseudo CO₂ pneumoperitoneum environ- ment at different pressure on invasion of hepatomcarcinoma cells in vitro by simulating laparoscopic surgery and explore the safety of laparoscopic hepatectomy and the clinical application on low pressure or gasless pneumoperitoneum.Methods: Human hepatomcarcinoma cells line SMMC-7721 were exposed to pseudo CO₂ pneumoperitoneum environment of different pressure (6, 9, 12, 15mmHg) for an hour. After exposion , Transwell chamber and MTT colorimetric assay were used to determine the invasion capacity, migration and adhesive ability of hepatomcarcinoma cells in vitro.Then the different time point expressions of MMP-9 and VEGF were detected by immunocytochemical stain to investigate the invasiveness of exposed hepatomcarcinoma cells line SMMC-7721.Results: Exposed groups of hepatomcarcinoma cells show gradually enhanced on invasion,migration and adhesive ability.The group of 9mmHg shows significantly enhanced on its adhesive ability compared with the control group (P<0.01).Then the group of 12mmHg shows significantly enhanced on its invasion and adhesive ability (respectively,P <0.05 and P <0.01).While the group of 15mmHg shows significantly enhanced on its invasion,migration and adhesive ability compared with the control group(respectively, P=0.008, P=0.015and P<0.01).The in vitro adhesive ability of all exposed groups of hepatomcarcinoma cells raised at a peak 48h after exposition, then drops at 72h and lower than 0h after exposition (12mmHg group and 15mmHg group were all P <0.05). the expressions of MMP-9 and VEGF of hepatomcarcinoma cells line SMMC-7721 rised gradually with the increased of CO₂ pressure.The MMP-9 expressions of the groups of 9mmHg, 12mmHg and 15mmHg are significantly rised compared with the control group (P<0.01),also the 12mmHg and 15mmHg groups were obviously higher on their expressions of VEGF compared with the control group(P<0.01).The protein expressions of MMP-9 and VEGF rise gradually and reach a peak at 24h after exposition, then decreased.Conclusion:High pressure CO₂ pneumoperitoneum environment can significantly promote the invasion of hepatomcarcinoma cells line SMMC-7721.The mechanism may due to obviously promotion of MMP-9 and VEGF expressions. Laparoscopic hepatectomy may use low-pressure pneumoperitoneum or gasless laparoscope to reduce the effect of CO₂ pneumoperitoneum on invasion capacity of malignant tumor.