Effects Of Different Degrees Of Necrotizing Enterocolitis On Brain Injury In Neonatal Mice

Objective:The purpose of this study was to investigate the effect of different degrees necrotizing enterocolitis on brain injury in neonatal miceand its possible mechanisms.Methods:Sixty 5-day old C57BL/6 mouse were randomly divided into control group(CON group,n=20)and necrotizing enterocolitis group(NEC group,n=40).NEC model was induced by formula gavage feeding+hypoxia+oral lipopolysaccharide(LPS).After 4 days of NEC modeling,all pups were sacrificed by cervical decapitation.The general conditions of mice were observed.HE staining was used to observe the pathological changes of intestinal tissue.NEC group was divided into mild NEC group and severe NEC group according to ileocecal intestinal injury score.Nissl staining was used to further observe the pathological changes of the corresponding brain tissue,and the correlation between the degree of intestinal injury and the number of nerve cells was analyzed.The m RNA levels of the inflammatory factors interleukin-1β(IL-1β),interleukin 6(IL-6)and tumor necrosis factor-α(TNF-α)in brain tissues were measurd by Quantitative real-time PCR(q RT-PCR).Enzyme-linked immunosorbent assay(ELISA)was used to detect the protein expression levels of the IL-1β,IL-6 and TNF-α in brain tissues.Immunofluorescence was used to detect the number of activated microglia and astrocytes in the hippocampus.Results:The results showed that the NEC group have lower weight and activity than the control group;Compared with the control group,the intestinal damage score of NEC mice was higher.Compared with the control group,the number of nerve cells in the hippocampus of NEC group decreased(P<0.05),and the number of nerve cells in severe NEC group decreased more than that in mild NEC group(P<0.05).Correlation analysis showed that the pathological changes of brain were positively correlated with the severity of intestinal injury(r= 0.943,P<0.001).Compared with the control group,the gene and protein levels of the IL-1β,IL-6 and TNF-αin brain tissues were significantly elevated(P<0.05)and the activated microglia and astrocytes were also significantly increased in NEC group(P<0.05),especially in severe NEC(P<0.05)Conclusion:Necrotizing enterocolitis can lead to the decrease and disorder of nerve cells in the brain tissue of mice,and the degree of damage is related to the severity of intestinal injury,which may be related to the increase of neuroinflammation.