The Effect Of The CO₂Pneumoperitoneum On The Expression Of TK-1and Ki67in Colorectal Carcinomas Cell

Objective:To investigate the influence of CO₂-insufflation with different pressure anddifferent exposed time on the expression of thymidine kinase-1and Ki67in colorectalcarcinomas cell.Methods:With an artificial CO₂pneumoperitoneum model in vitro, SW480coloncarcinoma cells were exposed to CO₂-insufflation at different pressure （6、9、12and15mmHg） for2and4hours. The without CO₂-insufflation groups were exposed to37℃、5%CO₂.The protein level of TK-1and Ki67were measured0、24、48and72hours （cultured in37℃、5%CO₂） after CO₂-insufflation using flow cytometry andthe mRNA level of these proteins were detected by reverse transcription PCR.Results:In protein level the expression of TK-1and Ki67on SW480cell line decreasedsignificantly in12、15mmHg CO₂-insufflation group in the same exposed time（P＜0.05），and the expression of the two proteins returned to the without CO₂-insufflationlevel by48、72h（P＞0.05）. With the CO₂-insufflation pressure ascending，theexpression of TK-1、Ki67was decreasing in the same exposed time；In the samepressure,the expression of TK-1and Ki67in15mmHg or12mmHg which exposed in4hours were lower than in2hours.The group of lower pressure（6mmHg）,there wereno significant difference between the groups of4hours and2hours.In the same exposed time，the transcription level the expression of TK-1、Ki67on SW480cell line decreased significantly in12、15mmHg CO₂-insufflation group（P＜0.05）. The expression of TK-1mRNA and Ki67mRNA returned to the withoutCO₂-insufflation level by48h（P＞0.05）.With the same CO₂-insufflation pressureascending，the differences of TK-1mRNA between the groups of4hours and2hourswere significant. Conclusion:The expression of TK-1and Ki67was suppressed temporarily after thecontinuous CO₂-insufflation in higher pressure（12、15mmHg）.In other word theproliferation of SW480were suppressed temporarily by higher pressure. The higherpressure of CO₂-insufflation,the more important role it played in inhibiting theexpression of the two proteins.The longer time of CO₂-insufflation,the moresignificantly it decreased the expression of them.