ObjectiveTo explore the protective effects and the mechanism of smectite powder in inhibit intestinal injury of neonatal SD rat necrotizing enterocolitis(NEC) model.MethodsAccording to 2×2 factor analysis, 32 neonate SD rats(48 hours olds, weighing 5～10 g) were divided into 4 groups(A1B1, A1B2, A2B1 and A2B2, n=8 rats each groups).Rats in group A1B1 and A1B2 were made into NEC models as follows: separate from mother rats and feeding with rat milk substitute, hypoxia(100%N2) for 90 second and 4 ℃ cold exposure for 10 minutes, twice a day during 3 consecutive days.Rats in group A1B1 was given smectite powder(0.6 g·kg-1·d-1) and rats in group A1B2 was not.Rats in groups A2B1 and A2B2 served as control groups, as well as rats in group A2B1 was given smectite powder(0.6 g·kg-1·d-1) and those in group A2B2 was not.On the 4th day all the subjects were sacrificed and intestinal tissues were obtained to examine.The intestine around ileocecal junction was for histological analysis and score.The mean scores more than 2 were considered NEC.The remaining intestine was used to measure the contents of secretory phospholipase A2(sPLA2) in homogenate of intestinal tissue by ELISA, and were expressed pg per mg protein of intestinal tissue.Kruskal-Wallis H test and factorial ANOVA were used to analyze difference among various groups.α=0.05 was considered significant.ResultNeonatal rats in groups A1B1 and A1B2 had diarrhea, abdominal distention, growth and development stepping down, activity reducing.As compared with group A1B2, there were remarkably relieved after given smectite powder in group A1B1.The score of histopatholigical and the content of sPLA2 in intestinal tissue had significant difference among groups.Comparing with that of group A1B2, the score of histopatholigical and the content of sPLA2 in intestinal tissue of group A1B1 reduced, but that of group A1B1 was higher than two control groups significantly.By factorial ANOVA, two factors of model and smectite powder intervention had taken effect on the score of histopatholigical and the contents of sPLA2 in intestinal tissue.ConclusionSmectite powder is beneficial to reduce the intestinal injury of NEC neonate rats and decrease the incidence of NEC of neonate rats.