The Effect Of Diet Selenium Deficiency On Proteome And Autophagy In Chicken Liver

Selenium(Se) is an essential trace element for animals and plays an important role in animal growth, development, reproduction, and others. Liver is one of main target organs in livestock and poultry when Se deficiency disease happens. Se deficiency disorders the liver metabolism function, cause liver cells damage, and even induces necrosis. At present, the mechanism of liver damage induced by Se deficiency has been extensively studied from the angle of oxidative stress and apoptosis, but the exact mechanism is still unclear. Therefore, further study on the mechanism of chicken liver damages induced by Se deficiency will greatly enrich the research content on this field.This study is performed on the basis of chicken liver damage model which induced by Se deficiency. In the present study, we observed the microstructure and ultrastructure of liver and detected the content or enzyme activity of oxidative stress related factors(GSH-Px, GSH, MDA, NO and i NOS), the mRNA levels of twenty-one selenoprotein genes(Gpx1 Gpx2, Gpx3, Gpx4, Sepn1, Sepp1, Selo, Sepx1, Selu, Txnrd1, Txnrd2, Txnrd3, Dio1, Dio2 and Dio3, SPS2, Seli, Selm, Sel Pb, Sep15 and Sels), heat shock protein gene family(Hsp27, Hsp40, Hsp60, Hsp70 and Hsp90) by real-time quantitative PCR method, and also detected the protein expression levels based on the proteomics technology to analyze the changed proteins and screen the related pathways; we also detected the m RNA levels of and autophagy related genes(LC3-1, LC3-2, ATG5, Dynein, TOR and Beclin1) by real-time quantitative PCR method and the protein levels(LC3-1, LC3-2, Dynein and Beclin1) by protein immunoblot method, in order to elucidate the pathogenesis of liver damage induced by Se deficiency from the angle of autophagy. The present study will elucidate the pathogenesis of chicken liver injury induced by Se deficiency from the angle of autophagy, and provide theoretical basis for prevention and treatment of liver damage induced by Se deficiency, and provide reference to the comparing medicine. The main results are as following:The pathological histology observation of liver showed that inflammatory infiltrates, liver structure damage, and necrosis, moreover the ultrastructure observation of liver cells showed that cellular structure(mitochondria, endoplasmic reticulum) were significantly damaged in chicken fed with Se deficiency diet. Autophagy was also observed evidently, which showed that it was involved in the process of liver injury induced by Se deficiency.It was showed that GSH-Px activity and content of GHS in liver tissue were gradually decreased with extended time, but the content of MDA and NO, and activity of i NOS showed a trend of gradually rising in Se deficiency group. It is significantly different with control group(P<0.05), which indicated that the oxidative stress was increased in the liver tissue with the extension of experiment.The results showed that the mRNA expression levels of 18 selenoprotein genes(Gpx1, Gpx2, Gpx3, Gpx4, Sepn1, Sepp1, Selo, Sepx1, Selu, Txnrd1, Txnrd2, Txnrd3, Dio1, Dio2, SPS2, Selm, Sel Pb and Sels) were decreased, Sep15 was firstly increased then decreased by Se deficiency. Compared with the control group, there are significant differences(P < 0.05) in the Se deficiency group, but Seli and Dio3 m RNA expression levels have no significant difference. The results indicated that the effect of Se deficiency on the expressions of different selenoprotein was different in chicken liver.Long time Se deficiency induced the m RNA expression of Hsp27, Hsp40, Hsp60 Hsp70 and Hsp90 to increase. In addition, the protein levels of Hsp60, Hsp70 and Hsp90 were also increased. The results showed that HSPs were involved in the liver injury induced by Se deficiency in chicken.By analyzing the proteomics, we found that Se deficiency increased 113 and decreased 95 different proteins in liver. KEGG metabolic Pathway analysis shows that these proteins mainly involved in autophagy related pathways. In addition, the pathway enrichment analysis for autophagy showed that these proteins were mainly involved in 6 autophagy signaling pathways, including the primary MARK and mTOR signaling pathways.Autophagy related genes, for instance, LC3-1, LC3-2, ATG5, Dynein and Beclin1 were in a time dependent manner in liver, but the TOR was firstly increased then decreased increased by Se deficiency. And there is a significant difference between control and Se deficiency group(P<0.05). Combined with morphology, it showed that autophagy was one pathological mechanism of Se deficiency induced liver injuries.In summary, Se deficiency induced oxidative stress and higher expression of HSPs in chicken liver. By proteomic analysis, we screened out that autophagy is the main signaling pathways in the process of liver injury which induced by Se deficiency. The morphology and autophagy related genes change indicated that autophagy is one pathological mechanism of liver injury induced by Se deficiency.The results enriched the pathological mechanism of Se deficiency liver damage, laid the foundation for further study about liver injury induced by Se deficiency and the comparing medicine.