Effect Of Hypotonic Enteral Feeding On Reduction Of Intestinal Injury In Neonatal Rat Nec Model And Complete Blood Counts For Identifying Surgical NEC In Preterm Infants Without Pneumoperitoneum

Necrotizing enterocolitis?NEC?is a devastating disease in the neonates,especially in preterms.The factors may lead to NEC includes enteral feeding,infections,hypoxia and other relative factors.Many studies has been conducted to protect the intestines,such as the use of EPO,EGF and prebiotics.These methods may be promising,but they are not widely used in patients because of the unknown risks.Since hyperosmolarity is a factor which can lead to intestinal defect,there is a possibility that hypotonic enteral feeding may reduce this effect.This study is divided into the following five parts:Part?:A total of 60 Sprague Dawley rats were included and subscribed into three groups:dam fed,isosmolarity?256mOsm/kg?+hypoxia+LPS,and hyperosmolarity?512mOsm/kg?+hypoxia+LPS group.The HE showed classical NEC manifestation,implying this model was successful.Part?.In order to study the role of hyposmolarity in the protection of intestinal epithelia barrier function,20 rats were included in the hyposmolarity?128mOsm/kg?+hypoxia+LPS group.This group showed longer villus comparing with hyper-and isosmolarity group.Electron microscopy showed more slight microvillus injury and shorter tight junction length.Part? We use immunofluorescence,RT-qPCR and Western Blot to test the expression of ZO-1 and Occludin.IF and Western Blot showed the protein levels were dam fed group>hyposmolarity group>isosmolarity group>hyperosmolarity group.The mRNA levels of ZO-1 were dam fed group<hyposmolarity/isosmolarity<hyperosmolarity;and the mRNA level of Occludin were dam fed group>hyposmolarity group>isosmolarity group>hyperosmolarity group.Part?.We use immunohistology and RT-qPCR to test the expression of MUC2.The mRNA level of MUC2 were hyposmolarity group>isosmolarity>hyperosmolarity>dam fed group.IHC results showed decreased protein expression of mucin in experimental groups,especially in iso-and hyper-groups.Part?We use immunofluorescence and Western Blot to test the expression of NF-?B.Results showed that the reduction of osmolarity of enteral feeding could reduced the activation of NF-?B.Part ? Patients were stratified by the need of surgery as surgical NEC?n=45?and medical NEC?n=43?.The values of WBC,PLT and CRP were collected at time before NEC occurred?T₀?,at onset of NEC?T₁?and when surgical assessment was required?T₂?.Patients admitted in the following period were collected for further verification.Variables identified in logistic regression analysis predicting surgical NEC were WBC and PLT at T₂?WBC₂ and PLT₂?.The predictive probability of surgery?P?could be calculated by the equation ln?P/?1-P??=2.725-0.191WBC₂-0.007PLT₂.The area under curve of P was 0.83and the ideal cutoff value was 0.55,with sensitivity and specificity of 83%and 81%,respectively.This cutoff value got an sensitivity of 84%and specificity of 86%in the verification group.In conclusion,the reduction of osmolarity of enteral feeding could protect the intestinal epithelial barrier function by preserving the tight junction and mucin,through decrease release of TNF-??IL-1??IL-6 mediated by NF-?B p65.Which more,we found the combination use of WBC and PLT can increase the accuracy in predicting surgical intervention.