Histological and ultrastructural changes induced by selenium in early experimental gastric carcinogenesis

Table 1 Groups of Wistar rats

Group	Number	Dose of MNNG (mg/kg)	Dose of selenium in water (mg/L)	Time of selenium given
Normal control	10	0	0	/
Experimental control	22	20	0	/
Low selenium	15	20	2	1 wk before MNNG gavage
High selenium	15	20	4	1 wk before MNNG gavage

Table 2 Results of pathologic diagnosis

	Number of rats	Incidence rate of leiomyoma (%)	Incidence rate of intestinal metaplasia (%)
Normal control	10	0	0
Experimental control	22	23	45.5
Low selenium	15	46.6	66.7a
High selenium	14	42.8	92.9a

^aP<0.05 vs experiment control group.