The Study On Apoptosis Of Selenium Deficiency In Broiler Brain Based On Endoplasmic Reticulum Stress Pathway

Selenium(Se),as an essential microelement in people and animals,play many important biological functions.Se deficiency causes kinds of diseases because of injuring structure and function of tissues.Brain as a target organ of selenium deficiency,its damage cannot be ignored.Se deficiency induce apoptosis in brain.However,the effect of Se deficiency on brain damage in broiler during exudative diathesis(ED)is little to report.Therefore,in this experiment,1801-day-briolers were divided into two groups randomly and equally:control group(C-group,fed with Se 0.282 mg/kg diet)and low group(L-group,fed with Se 0.033 mg/kg diet).During 16?35 days,the broilers with ED were executed right now and all the parts of brain(cerebra gray,white matter,cerebellum,thalamus,brainstem)were sampled.The ultrastructure of brain was observed and the mRNA levels,including genes regulated to endoplasmic reticulum stress(ERS)(GRP78,GRP94,IRE-1,XBP1,ATF4,ATF6,CHOP,ERO1?),calcium homeostasis(CAPN1?IP3R?RYR3?SERCA),and apoptosis(Caspasel2,Caspase3)were tested.Then,the relative express of proteins about endoplasmic reticulum stress(GRP78,CHOP)and apoptosis(Caspasel2,Caspase3)were evaluated by Western Blot.The object of this study is to discuss the effect of Se deficiency on the injury of different brain regions in ED broiler and the role of ERS in brain apoptosis.The results were showed as following:(1)Obvious pathological changes appeared in ultrastructure of ED broiler brain,nuclear membrane shrinkage,even buds;nuclear enrichment were observed,chromosome gathered themselves together;endoplasmic reticulum,rough endoplasmic reticulum was reduced obviously,mitochondria became swelling and a large number of vacuoles could be observed,the cristae was broken or gone;(2)Se deficiency could increase the mRNA(GRP78,GRP94,IRE-1,XBP1,ATF4,ATF6,CHOP)and protein(GRP78)levels of genes related to ERS and it declared that ERS was happened in brain religion of ED broiler induced by Se deficiency;(3)Se deficiency could increase the mRNA levels of calcium transportation proteins IP3R,RYR3 and CAPN1,which indicated that Se deficiency could disturb calcium balance in brain regions of ED broiler thereby damaging the brain tissue;(4)Se deficiency could up-regulate the mRNA and protein levels of pro-apoptotic genes(Caspasel2,Caspase3),and the effect of Se deficiency on thalamus and brainstem was the most significant,which implied that Se deficiency induced apoptosis in brain tissue of ED broiler.In conclusion,Se deficiency up-regulated the mRNA levels of ER stress indexes and activated CHOP and EROla.Then calcium homeostasis was disturbed and apoptosis was induced by Se deficiency via CHOP/Caspase3 pathway.