Objective    To discuss the effect of  CO

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artificial pneumoperitoneum on the invasion of the  endometrial cancer in  nude mouse resulted from the transplantation of the cancer cells and its mechanism.     Methods    Thirty nude mice were divided into 3 groups based on the time in the CO

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  pneumoperitoneum circumstance.  Control group: the small intestine of the nude mouse was exposed in air for 5 min

and the cancer cells were injected into right lower quadrant after suture.  The gas was depleted after 40 min.  40 min group: CO

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gas was poured into abdominal cavity to form a 4 mmHg artificial pneumoperitoneum for 5 min before cancer cells were injected into right lower quadrant. The gas were depleted after 40 min. 80 min group: CO

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gas was poured into abdominal cavity to form a 4 mmHg artificial pneumoperitoneum for 5   min before cancer cells were injected into right lower quadrant. The gas were depleted after 80 min.  The time that each group took to form a solid tumor was recorded.  Four weeks later

the transplantation tumors were taken out and sliced into frozen sections and paraffin-embedded sections.   The expression of β

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-intergrin and E-cadherins was detected by IMF.     Results    The time taken to form the solid cancer was shorter in the 40 min group and 80 min group than in the control group

with more blood vessel found (P0.05).  β

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-intergrin expression in the 2 test groups was obviously lower that that in the control group (P0.01) and the 80 min group was lower than the 40 min group (P0.05). E-cadherins expression in the control  group was higher than that in the test group. (P0.01)

and no difference was found in the 2 test groups (P0.05).      Conclusion    The CO

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  pneumoperitoneum could enhance the abilities of invasion and adhesion of endometrial cancer cells

which is  associated with the expression changes  of β

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-intergrin and E-cadherins in the cancer cells.