| Neonatal asphyxia is a common disease during perinatal period, which happen in uterus and during laboring. To analyze the variation of hemodynamics of multiple organs in asphyxiated neonates, It have been found that the blood flow of celiac trunk artery decrease by 70 percent , which cause the blood flow of gastrointestinal tract drop off and lead to gastrointestinal lesions, such as ulcer, bleeding even ne-crotizing enterocolitis ( NEC). It was noted that gastrointestinal lesions was occurred in 29 percent of asphyxiated neonates in Spain, whereas gastrointestinal lesions was involved in 30. 3 percent of asphyxiated neonates in our nation.Recent investigations have suggested that several growth factors participate in the series of reparative events after acute gastrointestinal lesions. Of these growth factors, epidermal growth factor (EGF) appears to play an important role in the development of gastrointestinal tract, the inhibition of gastric acid secretion, protecting gastrointestinal tract and promoting gastrointestinal lesions healing by binding its receptor (epidermal growth factor receptor, EGFR).Fetus Wistar rats of 21 days gestation age were used to make asphyxia model. The expressionss of EGF and EGFR in gastrointestinallesions of asphyxiated newborn rats were assayed by histological , im-munohistochemistry and RT - PCR methods.Methods1 Animal modelThe pregnant 21 days Wistar rats were anesthetized with ether. After two - horn uterus and vessels supplying uterus and ovary were exposed, arterial clamps occluded one side of vessels. Another side was regarded as control group. The planned occluding time was 20 min. Then uterus was opened rapidly and pups were removed. After dealing with keeping warm , inhalation oxygen et al methods , the survival pups were fed by other Wistar rats.2 Methods(1)Gastrointestinal EGF and EGFR were assayed by immunohisto-chemistry method in different time points of asphyxiated newborn rats.(2)The expressions of EGFR mRNA in gastric mucous were assayed by RT - PCR in different time points of asphyxiated newborn rats.(3)Histology changes of gastrointestinal tissue samples were studied by HE.3 Statistics; Data were expressed as X ± SD. Data were analyzed by SPSS software with q test. If p < 0. 05 , the difference was significant.Results1 The expressions of EGF in gastrointestinal tract of normal new-born rats was predominant in cytoplasm of epithelial cells, but immu-nostained slightly. The average gray density of EGF in gastrointestinal tract of asphyxiated newborn rats increased following their growth and reached peak in the group of 48 hours after birth ( p < 0. 05 ) , then began to decrease gradually. The average gray density of EGF in gastrointestinal tract of control group didnt occur such change.2The expressions of EGFR in gastrointestinal tract of normal newborn rats was predominant in membrane of epithelial cells, but im-munostained slightly. The average gray density of EGFR in gastrointestinal tract of asphyxiated newborn rats decreased significantly in the group of 0 hour, then increased gradually and reached peak in the group of 48 hours after birth ( p < 0. 05 ) , then began to decreased gradually. The average gray density of EGFR in gastrointestinal tract of control group didnt occur such changes.3 The expressions of EGFR mRNA in gastrointestinal tract of asphyxiated newborn rats decreased significantly in the group of 0 hour ( p < 0. 05 ) , then began to increase gradually and reached peak in the group of 24 hours after birth, then decreased gradually. The expressions of EGFR mRNA in gastrointestinal tract of normal newborn rats didnt occur such changes.4 Histology changes of gastrointestinal tissue samples were obvious in asphyxia groups, especially in the group of 48 hours.Conclusion(l)The expressions of EGF in gastrointestinal tract of asphyxiated newborn rats gradually increased following the increasing of the degree of gastrointestinal lesions and reached peak at 48 hours, then began to... |
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