Temporal profile of intestinal tissue expression of intestinal fatty acid-binding protein in a rat model of necrotizing enterocolitis

OBJECTIVES: Necrotizing enterocolitis is a severe multifactorial intestinal disorder that primarily affects preterm newborns, causing 20-40% mortality and morbidity. Intestinal fatty acid-binding protein has been reported to be a biomarker for the detection of intestinal injuries. Our aim was to assess intestinal tissue injury and the molecular expression of intestinal fatty acid-binding protein over time in a necrotizing enterocolitis model. METHODS: A total of 144 Newborn rats were divided into two groups: 1) Control, which received breastfeeding (n=72) and 2) Necrotizing Enterocolitis, which received formula feeding and underwent hypoxia and hypothermia (n=72). A total of six time points of ischemia (2 times a day for 3 days; 12 pups for each time point) were examined. Samples were collected for analysis of body weight, morphological and histological characteristics, intestinal weight, intestinal weight/body weight ratio, injury grade, and intestinal fatty acid-binding protein levels. RESULTS: Body and intestinal weights were lower in the Necrotizing Enterocolitis group than in the Control group (p<0.005 and p<0.0005, respectively). The intestinal weight/body weight ratio was higher in the Necrotizing Enterocolitis group than in the Control group (p<0.005) only at the sixth ischemia time point. The Necrotizing Enterocolitis group displayed higher expression of intestinal fatty acid-binding protein (p<0.0005) and showed greater tissue damage than the Control group. CONCLUSION: Intestinal fatty acid-binding protein was an efficient marker of ischemic injury to the intestine and a good correlation was demonstrated between the time of ischemic injury and the grade of intestinal injury.

Incremento de la expresión de Bax (proapoptótico) y disminución de la expresión de Bcl-2 (antiapoptótico) en recién nacidos con enterocolitis necrosante / Increase in pro-apoptotic Bax expression and decrease in anti-apoptotic Bcl-2 expression in newborns with necrotizing enterocolitis

Antecedentes/Objetivo: El objetivo de este estudio fue determinar si se producía un incremento de la expresión de Bax (proapoptótico) y una disminución de la expresión de Blc-2A1 (antiapoptótico) en el intestino de los recién nacidos con enterocolitis necrosante. Materiales y métodos: Comparamos a ocho pacientes recién nacidos de manera consecutiva sometidos a resección intestinal debido a enterocolitis necrosante con ocho recién nacidos sometidos a resección intestinal debido a atresia ileal. La evaluación histopatológica de la lesión tisular y la apoptosis se realizó mediante microscopía óptica y el método TUNEL. El nivel de ARNm en los genes apoptóticos (CASP3, CASP6, CASP7, Bax, BIRC2) y antiapoptóticos se evaluó con el método de matriz de RCP (PCR array). La expresión de proteínas se evaluó mediante inmunohistoquímica. Resultados: Los puntajes de las lesiones tisulares y los puntajes medios de apoptosis fueron significativamente más altos en el grupo con enterocolitis necrosante en comparación con el grupo de referencia (p < 0,01). La expresión de los genes proapoptóticos aumentó significativamente en el grupo con enterocolitis necrosante frente al grupo de referencia (p < 0,01). La expresión del gen Bcl-2A1 (antiapoptótico) disminuyó significativamente en el grupo con enterocolitis necrosante (p < 0,01). La expresión de las proteínas Bax y CASP3 aumentó significativamente en el grupo con enterocolitis necrosante (p < 0,01). Conclusión: Según nuestros datos, la alteración del equilibrio entre la expresión de Bax (proapoptótico) y la expresión de Bcl-2A1 (antiapoptótico) en el lugar de la lesión es un posible mecanismo de la patogenia en recién nacidos que presentan enterocolitis necrosante.

Background/Aim. The aim of the present study was to find out if there is an increase in the expression of pro-apoptotic Bax and reduction in expression of anti-apoptotic Blc-2A1 in newborn intestines with necrotizing enterocolitis (NEC). Material and Methods. We compared 8 consecutive newborn patients undergoing bowel resection for NEC with 8 neonates undergoing intestinal resection for ileal atresia. Histopathological evaluation of tissue injury and apoptosis was performed by using light microscopic examination and TUNEL method. The mRNA level of apoptotic (CASP3, CASP6, CASP7, Bax, BIRC2) and anti-apoptotic genes were evaluated by PCR array method. Protein expression was assessed by immunohistochemistry. Results. Tissue injury scores and mean apoptosis scores were significantly higher in NEC group when compared with control group (p <0.01). Expression of pro-apoptotic genes were significantly increased in NEC group when compared with control group (p <0.01). Expression of anti-apoptotic Bcl-2A1 gene was significantly decreased in NEC group, (p <0.01). Protein expression of Bax and CASP3 was significantly increased in NEC group, (p <0.01). Conclusion. Our data in humannewborns suggest that alteration of the balance between pro-apoptotic Bax expression and anti-apoptotic Bcl-2A1 expression in the site of injury is a possible mechanism in the pathogenesis of NEC.

L-FABP and I-FABP expression in newborn rats changes inversely in the model of necrotizing enterocolitis

PURPOSE: To determine the expression of hepatic L-FABP and intestinal I-FABP in an experimental model of necrotizing enterocolitis (NEC) in neonatal rats. METHODS: Newborn Sprague-Dawley rats were divided into four groups: Control (C1) - exclusive breastfeeding at the first and sixth procedures (C6), NEC1 - fed formula milk and submitted to hypoxia and hypothermia at the first and sixth procedures (NEC6). The newborn pups were fed twice a day for three days, for a total of six procedures. Samples were collected for morphometric evaluation (body weight, liver weight, liver weight/body weight ratio, intestinal weight and intestinal/body weight ratio) and for immunohistochemical and Western blotting analysis. The values obtained were analyzed statistically, with the level of significance set at p<0.05. RESULTS: Morphometric measurements showed reduction of body and liver weights in the NEC group (p<0.05). Both immunohistochemistry and western blotting revealed that L-FABP expression in the liver was decreased and I-FABP expression in the ileum was increased in the NEC group (p<0.05). CONCLUSION: L-FABP and I-FABP expression changed inversely in the rat NEC model. These findings can contribute to a better diagnosis of NEC in human newborns. .