Effect And Significance Of Intestional Trefoil Factor In Neoratal Rat Model Of Necrotizing Enterocolitis

Objective:To study the effects of intestinal trefoil factor (ITF) on the contents of proinflammatory cytokines(IL-1β,IL-6) and antiinflammtory cytokines(IL-10) following Necrotizing Enterocolitis (NEC), to study effects of ITF on the regulation of NF-κB signaling in necrotizing enterocolitis models. Here we investigated activation of MAPK signaling transduction pathway occurs during asphyxia/cold stressed NEC in neonatal rats.Methods:Fifty neonatal rats were randomly divided into five groups:Group A, normal control; Group B, normal control+ITF 0.2mg; Group C, NEC; Group D, NEC +N.S 0.2ml; Group E, NEC+ITF 0.2mg. NEC model of neonatal rats were established as followed:Hypoxia was accomplished by stressing each rat pup with 100% N2 for 1 min, followed by exposure to cold (4℃) for 10 min two times daily. Rats were killed on the fourth day, and distal ileum was harvested for morphological studies and immunohistochemistry for NF-κB (p65) and MAPK, the contents of IL-1β, IL-6 and IL-10 of intestinal tissue were measured using commercial ELISA assay kits.Results:The pathological lesions indicated that severe separation of submucosa and lamina propria and tissue necrosis in group C and D, and slight submucosal and lamina propria separation in group E.Content of IL-1βwas dramatically less in group E than that in group C and D(P<0.01), but no differences were found between E and A, B(P >0.05). Content of IL-6 was dramatically less in group E than that in group C and D(P <0.01), but no differences were found between E and A, B(P>0.05). Content of IL-10 was dramatically more in group E than that in group A, B and C, D(P<0.01). In normal intestinal tissue, there is no or only a veryweak staining for NF-κB(p65) observed. In the NEC model, immunohistochemical staining for NF-κB(p65) was shown as strong brown color and was distributed in intestinal epithelium. Treatment with ITF by hypodermic injection significantly decreased the immunoreactivity of NF-κB(p65) in the NEC model. Induction of NEC by asphyxia/cold stress increased phosphorylation of the 3 major MAPKs:MEK/ERK/Elk-1, p38, and JNK/c-Jun. Administration of the drug ITF activatied phosphorylation of MEK/ERK/Elk-1, however no differences of activation of JNK/c-Jun and p38 were found between C, D and E.Conclusion:Intestinal inflammation was ameliorated after ITF was injected hypodermically. ITF may protect the intestinal injury of neonatal rat NEC model by suppression of inflammatory response. Our results implicate activation of MAPK signaling transduction pathway occurs during asphyxia/cold stressed NEC in neonatal rats and support the hypothesis that ITF might play a therapeutic role by actvation of MEK/ERK/Elk-1 signaling transducton pathway in intestinal injure characterized by this animal model.