Effects of simulated carbon dioxide and helium peumoperitoneum on proliferation and apoptosis of gastric cancer cells

Table 2 Changes of culture media pH in helium groups (n = 4) (mean ± SD)

Groups	Time (h)
	0	2	4	6	8
Control	7.20 ± 0.01	7.18 ± 0.02	7.15 ± 0.01	7.17 ± 0.03	7.20 ± 0.02
0 mmHg	7.42 ± 0.02b	7.23 ± 0.03	7.18 ± 0.01	7.15 ± 0.01	7.16 ± 0.03
5 mmHg	7.53 ± 0.03b	7.28 ± 0.02b	7.21 ± 0.02a	7.19 ± 0.03	7.15 ± 0.01
10 mmHg	7.82 ± 0.02b	7.31 ± 0.01b	7.23 ± 0.02b	7.20 ± 0.05	7.15 ± 0.02
15 mmHg	8.19 ± 0.04b	7.96 ± 0.03b	7.33 ± 0.05b	7.22 ± 0.01	7.19 ± 0.02

^aP < 0.05 vs control group,

^bP < 0.01 vs control group.