Endoplasmic reticulum stress induced cell autophagy in the pathogenesis of necrotizing enterocolitis rats / 中国新生儿科杂志

ABSTRACT

Objective:To study the effects of endoplasmic reticulum stress (ERS) and autophagy mechanisms in the pathogenesis of necrotizing enterocolitis (NEC).Methods:A total of 39 newborn SD rats were randomly assigned into 3 groups: the NEC group (NEC model: artificial feeding+hypoxic stimulation+intragastric injection of lipopolysaccharides), the ERS antagonist group (NEC model+intraperitoneal injection of 4-phenylbutyric acid) and the ERS inducer group (NEC model+intraperitoneal injection of tunicamycin). After successful modeling, the rats were sacrificed and intestinal tissues were obtained. The intestinal pathology was observed using electronic microscope. Intestinal fatty acid binding protein (I-FABP) was detected using ELISA. Real-time quantitative polymerase chain reaction (RT-qPCR) was used to examine mRNA levels of glucose-regulated protein 78 (GRP78) and oxygen-regulated protein 150 (ORP150). Western-blot was used to detect p62 and autophagy-related proteins (microtubule-associated protein 1 light chain 3 (LC3)Ⅱ and LC3Ⅰ) and LC3Ⅱ/LC3Ⅰ ratio was calculated.Results:(1) For all 3 groups, the pathological scores of rat intestines were≥2. (2) The ERS inducer group showed significantly higher clinical score, pathological score, I-FABP level, GRP78 and ORP150 mRNA levels and LC3Ⅱ/ LC3Ⅰ ratio than the NEC group and ERS antagonist group, and the NEC group higher than the ERS antagonist group ( P<0.05). The p62 level in the ERS inducer group was significantly lower than the NEC group and the ERS antagonist group, and the NEC group lower than the ERS antagonist group ( P<0.05). (3) The LC3Ⅱ/ LC3Ⅰ ratio was positively correlated with clinical score, pathological score and I-FABP level ( P<0.05). The p62 level was negatively correlated with clinical score, pathological score and I-FABP level ( P<0.05). The mRNA levels of GRP78 and ORP150 were positively correlated with clinical score, pathological score and I-FABP level ( P<0.05). LC3Ⅱ/ LC3Ⅰ ratio was positively correlated with the mRNA levels of GRP78 and ORP150 ( P<0.05). The p62 level was negatively correlated with the mRNA levels of GRP78 and ORP150 ( P<0.05). Conclusions:ERS is associated with the pathogenesis of NEC. Inhibition of ERS can reduce autophagy and improve intestinal barrier function and clinical symptoms of NEC.