We investigated the lethal effect of a hyperthermic CO₂ pneumoperitoneum on gastric cancer cells. This could form the theoretical basis for further studies of the feasibility and safety of inflating hyperthermic CO₂ in the abdominal cavity of gastric cancer patients during laparoscopy.

An in vitro hyperthermic CO₂ pneumoperitoneum experimental model was built, where gastric cancer cell line SGC-7901 cells were grouped according to temperature. Cytotoxicity was detected using a cell counting kit; apoptosis was detected by Annexin V-FITC/PI flow cytometry and Hoechst 33342/PI fluorescent microscopy. Morphological alterations were observed by transmission electron microscopy. Invasion and migration were detected by a scratch test and by transwell migration, respectively.

Cytotoxicity assays showed that a hyperthermic CO₂ pneumoperitoneum significantly inhibited the proliferation of SGC-7901 cells (P<0.05); it also significantly induced apoptosis of SGC-7901 cells (P<0.05). Morphological observations showed that the cell membrane and nucleus had an apoptotic phenotype. The invasiveness and migration ability of the gastric cancer cells subjected to hyperthermic CO₂ were significantly reduced.

A hyperthermic CO₂ pneumoperitoneum had a lethal effect on gastric cancer SGC-7901cells by inhibiting their invasion and migration, and by inducing apoptosis.