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

Table 1 Changes of culture media pH in CO₂ groups (n = 4) (mean ± SD)

Groups	Time (h)
	0	2	4	6	8
Control	7.20 ± 0.02	7.18 ± 0.02	7.15 ± 0.01	7.16 ± 0.03	7.20 ± 0.02
0 mmHg	7.13 ± 0.04b	7.15 ± 0.03	7.15 ± 0.03	7.19 ± 0.01	7.23 ± 0.04
5 mmHg	7.00 ± 0.05b	7.13 ± 0.03	7.22 ± 0.02	7.22 ± 0.02	7.24 ± 0.02
10 mmHg	6.77 ± 0.03b	6.95 ± 0.05b	7.16 ± 0.03	7.22 ± 0.01	7.21 ± 0.01
15 mmHg	6.18 ± 0.02b	6.91 ± 0.02b	7.08 ± 0.04	7.20 ± 0.02	7.22 ± 0.01

^bP < 0.01 vs control group.

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.

Table 3 Changes of MKN-45 proliferative viability in CO₂ groups (OD, mean± SD)

Groups	Time (d)
	1	2	3	4	5	6	7
Control	0.31 ± 0.04	0.41 ± 0.02	0.53 ± 0.09	1.38 ± 0.04	1.81 ± 0.09	2.33 ± 0.04	2.33 ± 0.06
0 mmHg	0.28 ± 0.06	0.41 ± 0.04	0.56 ± 0.06	1.37 ± 0.07	1.58 ± 0.02	2.38 ± 0.06	2.39 ± 0.08
5 mmHg	0.31 ± 0.05	0.35 ± 0.05	0.56 ± 0.04	1.34 ± 0.04	1.59 ± 0.07	2.50 ± 0.07	2.32 ± 0.04
10 mmHg	0.29 ± 0.02	0.36 ± 0.04	0.53 ± 0.05	1.27 ± 0.05	1.57 ± 0.14	2.54 ± 0.10	2.40 ± 0.03
15 mmHg	0.32 ± 0.03	0.39 ± 0.05	0.47 ± 0.05	0.68 ± 0.04b	0.80 ± 0.04b	1.16 ± 0.08b	1.42 ± 0.02b

^bP < 0.01 vs control group; OD: Optical density.

Table 4 Changes of MKN-45 proliferative viability in helium groups (OD, mean± SD)

Groups	Time (d)
	1	2	3	4	5	6	7
Control	0.29 ± 0.04	0.36 ± 0.04	0.58 ± 0.03	1.22 ± 0.05	1.83 ± 0.03	2.21 ± 0.04	2.62 ± 0.04
0 mmHg	0.30 ± 0.02	0.39 ± 0.02	0.60 ± 0.04	1.23 ± 0.06	1.86 ± 0.06	2.37 ± 0.05	2.64 ± 0.05
5 mmHg	0.30 ± 0.02	0.38 ± 0.03	0.58 ± 0.03	1.27 ± 0.05	1.80 ± 0.08	2.40 ± 0.33	2.75 ± 0.12
10 mmHg	0.31 ± 0.03	0.41 ± 0.03	0.57 ± 0.05	1.25 ± 0.06	1.78 ± 0.04	2.49 ± 0.26	2.71 ± 0.18
15 mmHg	0.33 ± 0.02	0.39 ± 0.04	0.54 ± 0.09	1.24 ± 0.23	1.81 ± 0.09	2.31 ± 0.20	2.73 ± 0.11

OD: Optical density.

Table 5 Changes of MKN-45 apoptosis ratio in CO₂ and helium groups (%, mean ± SD)

Groups	Control	0 mmHg	5 mmHg	10 mmHg	15 mmHg	F
CO2	0.21 ± 0.02	0.19 ± 0.04	0.29 ± 0.05	9.20 ± 0.44a	11.60 ± 0.95a	430.09
He	0.28 ± 0.04	0.27 ± 0.04	0.31 ± 0.08	0.35 ± 0.11	0.37 ± 0.05	0.99

^aP < 0.05 vs control group; CO₂: Carbon dioxide; He: Helium.