Abstract: Objective Based on the expression of COX-2,the effect and mechanism of vitamin A and vitamin E in alleviating intestinal injury in neonatal rats with necrotizing enterocolitis(NEC)were explored. Methods The neonatal rats were randomly divided into control group,model group,positive drug sulfasalazine group,vitamin A group,vitamin E group,vitamin A + vitamin E group(A+E group).The pathological damage of the rat intestinal tissue was evaluated by HE staining.The apoptosis rate of the intestinal tissue was detected by TUNEL staining.The superoxide dismutase(SOD),glutathione peroxidase(GSH-Px),and malondialdehyde(MDA)in the intestinal tissue were detected by the kit.The mRNA and protein expression levels of TNF-α,IFN-γ and IL-10 in serum were detected by ELISA,and the mRNA and protein expression levels of TNF-α,IFN-γ,IL-10 and COX-2 in the intestinal tissue were detected by qRT-PCR and Western blot assays,respectively. Results Compared with the control group,necrosis villus structure destruction and transmastic necrosis occurred in intestinal tissue,apoptosis rate of intestinal tissue was significantly increased(P<0.05),the levels of SOD and GSH-Px were significantly down-regulated(P<0.05),and the level of MDA was significantly up-regulated(P<0.05);the levels of TNF-α and IFN-γ in serum were significantly up-regulated(P<0.05),the level of IL-10 was significantly down-regulated(P<0.05);the mRNA and protein levels of TNF-α,IFN-γ,and COX-2 in the intestinal tissue were significantly down-regulated(P<0.05),and the expression of IL-10 was significantly down-regulated(P<0.05)in the model group.Compared with the model group,pathological damage of intestinal tissue was alleviated in positive drug group,vitamin A group,vitamin E group,A+E group,apoptosis rate of intestinal tissue was significantly decreased(P<0.05),the levels of SOD and GSH-Px in intestinal tissue were significantly up-regulated(P<0.05),and the level of MDA was significantly down-regulated(P<0.05);the levels of TNF-α and IFN-γ in serum were significantly down-regulated(P<0.05),and the level of IL-10 was significantly up-regulated(P<0.05),the mRNA and protein levels of TNF-α,IFN-γ,and COX-2 in the intestinal tissue were significantly up-regulated,and the expression of IL-10 was significantly up-regulated(P<0.05),and the effect of the A+E group was significantly better than that of positive drug group(P<0.05). Conclusion The combination of vitamin A and vitamin E alleviates intestinal damage in NEC rats by inhibiting intestinal inflammation and oxidative stress,and the mechanism may be related to the inhibition of COX-2 expression.

Key words: vitamin A, vitamin E, necrotizing enterocolitis, COX-2, inflammation, oxidative stress