Inhibitory effect of sulindac against chemically-induced primary colonic tumors by N-methyl-N-nitrosourea in mice

Table 1 The experimental design and animal groups

Group	No.	MNU intraducal time (wk)	Sulindact time (wk)
Experiment one
Sulindac group	24	12	18
Control group	24	12	No
Experiment two
Sulindac group	24	12	18
Control group	24	12	No

Table 2 Effect of sulindac on the morphological characteristics of colorectal tumors induced by N-methyl-N-nitrosourea

	Experiment one		Experiment two
	Sulindacgroup	Control group	Control group	Sulindacgroup
Average number of adenoma	4.7	8.4	3.5	4.7
Average number of adenocarcinoma	9.3	3.9	8.7	9.4
Average ratio of adenoma to adenocarcinoma	0.51	2.15	0.40	0.50

Table 3 Effect of sulindac on the number of colorectal tumors induced by N-methyl-N-nitrosourea

	Experiment one		Experiment two
	Sulindacgroup	Control group	Control group	Sulindacgroup
No. of mice	24	24	24	24
No. of mice with tumors	19	9	21	20
No. of mice without tumors	5	15	3	4
Incidence of mice with colon tumors (%)1	79.2	37.5	87.5	83.3
No. of tumors2
0	5	15	3	4
1-3	11	8	8	7
4-6	4	1	5	7
7-9	1	0	5	3
10-12	1	0	2	2
13-16	0	0	1	1

¹χ² test, Experiment one: χ² = 7.563, P < 0.01; Experiment two: χ² = 1.003, P > 0.05.

²Wilcoxon rank test, Experiment one: μ = 5.078, P < 0.01; Experiment two: μ = 1.611, P > 0.05.

Table 4 Effect of sulindac on the volume of the colorectal tumor induced by N-methyl-N-nitrosourea

	Experiment one		Experiment two
	Sulindacgroup	Control group	Control group	Sulindacgroup
Median tumor diameter (mm)1
< 1	5	5	8	6
1.1-1.5	4	1	4	5
1.6-2.0	4	2	5	4
2.1-2.5	3	1	2	3
2.6-2.9	2	0	1	1
> 3.0	1	0	1	1
Median tumor volume (mm3)2
1-3	5	4	7	7
4-6	4	3	3	3
7-9	3	1	4	4
10-13	2	1	2	3
14-16	1	0	2	1
17-20	2	0	1	0
21-24	1	0	1	1
> 25	1	0	1	1

¹Wilcoxon rank test, Experiment one: μ = 8.155, P < 0.01; Experiment two: μ = 1.464, P > 0.05.

²Wilcoxon rank test, Experiment one: μ = 5.500, P < 0.01; Experiment two: μ = 1.333, P > 0.05.