Alleviative Effect Of Selenium On Chicken Nervous Poisoning Caused By Lead

Lead(Pb)is widely used in life and industrial production.Pb is a common environmental pollutant.Pb not only cause environment pollution but also has adverse effect on human and bird health.Pb can enter human and animal body through contaminated air,water,soil through food chains into the human and animal body,accumulated in the brain tissue,causing damage to the nervous system.Nervous system is one of the target organ poisoning.Selenium(Se)is one of the essential trace elements in organisms.Se has effects of antioxidant,anti-cancer,enhancing immune function,and alleviating heavy metal toxicity.The aim of this study was to discuss the mitigation effect of Se on chicken neurotoxicity induced by Pb,and to provide a basic data for better understanding of the alleviation effect of Se on Pb toxicity in chicken nervous tissues,and to provide reference for enriching the toxicology of Pb and the protection mechanism of Se.In this study,we investigated effect of Pb poisoning on chicken nervous tissues and alleviative effect of Se on Pb poisoning by detect chicken brain white matters,gray matters,cerebellums,thalamus,and brainstem,and chicken embryonic neurocytes.One hundred and eighty 1-day-old healthy Hyline male chickens were fed a standard commercial diet(containing 0.49 mg/kg Se)and drinking water for 7 days.Chickens were randomly divided into four groups(45 chickens per group)at 8 days of age.The control group was fed the standard commercial diet and drinking water.The Se group was fed sodium selenite added to the standard commercial diet at 1 mg/kg Se and drinking water.The Pb group was fed the standard commercial diet and lead acetate added to drinking water at 350 mg/L Pb.The Se/Pb group was fed Na2 Se O3 added to the standard commercial diet at 1 mg/kg Se and(CH3COO)2Pb added to drinking water at 350 mg/L Pb.Fifteen chickens per group were randomly selected and euthanised on the 30 th,60th,and 90 th days of the experiment,respectively.Next,chicken brain white matters,gray matters,cerebellums,thalamus,brainstem tissues were quickly removed and rinsed with ice-cold sterile deionized water.Chicken embryonic neurons were divided into control group,Se group(10-7 mol/L Se),Pb group(10-6 mol/L Pb),Se/Pb group(10-7 mol/L Se,10-6 mol/L Pb),and were cultured for 12,24,36 and 48 hours after the test.The following experiment was carried out:Antioxidant indicator(SOD,GPx,GST,CAT,T-AOC and NOS,MDA,NO,H2O2 and GSH)in brain(white matters),cerebellums,thalamus and chicken embryonic neurocytes;selenoproteins(GPx1,GPx2,GPx3,GPx4,Txnrd1,Txnrd2,Txnrd3,Dio1,Dio2,Dio3,Sel T,Sel K,Sel S,Sel H,Sel M,Sel U,Sel I,Sel O,Selpb,Sepn1,Sepp1,Sepx1,Sepw1,Sep15,and SPS2)in chicken brain white matters,gray matters,cerebellums,thalamus,brainstems,and chicken embryonic neurocytes;cytokines(IL-2,IL-4,IL-6,IL-12,IL-17,and IFN-γ);heat shock proteins(HSP27,HSP40,HSP60,HSP70,and HSP90);m RNA expression of apoptosis related factors(Bcl-2,p53,Bax,Cyt c and Caspase-3);microstructure and ultrastructure observation of brain white matters,gray matters,cerebellums,thalamus and brainstems tissue,AO/EB staining in chicken embryonic neurocytes.The results of the studies are listed as follows:(1)Pb inhibited SOD,GPx,GST,CAT,T-AOC,and NOS activities,induced MDA,H2O2 and NO contents,inhibted GSH contents in chicken brain tissues and chicken embryonic neurocytes.In the Pb group,MDA content increased with the increase of time in brain white matters,and had a time effect.Se alleviated Pb-caused changes of above antioxidant indexin chicken brain tissues and embryonic neurocytes.Pb caused oxidative stress.Se alleviated Pb-causedoxidative stress.(2)Pb inhibited m RNA expression of twenty-five selenoproteins(GPx1,GPx2,GPx3,GPx4,Txnrd1,Txnrd2,Txnrd3,Dio1,Dio2,Dio3,Sel T,Sel K,Sel S,Sel H,Sel M,Sel U,Sel I,Sel O,Selpb,Sepn1,Sepp1,Sepx1,Sepw1,Sep15,and SPS2)in chicken brain tissues and chicken embryonic neurocytes.In the Pb group,Txnrd3 mRNA expression in thalamus and brainstems,Sel U and Sel O m RNA expression in the thalamus,SPS2 mRNA expressionin the cerebellums,and Sel U m RNA expression in the chicken embryonic neurocytes decreased with the increase of time,and had time effects.Se alleviated Pb-caused changes of above twenty-five selenoproteins in chicken brain tissues and embryonic neurocytes.(3)Pb inhibited IL-2 and IFN-γ mRNA expressionin in chicken brain tissues and chicken embryonic neurocytes;Pb induced IL-4,IL-6,IL-12β and IL-17 m RNA expression.In the Pb group,IFN-γ m RNA expression in gray matters decreased with the increase of time,IL-4 and IL-12β mRNA expression in brainstems increased with the increase of time,and had time effects.Se alleviated Pb-caused changes of inflammation related factors.Pb caused immunosuppression and inflammatory response.Se alleviated Pb-caused immunosuppression and inflammatory responsein chicken brain tissues and embryonic neurocytes.(4)Pb induced m RNA expression of HSP27,HSP40,HSP60,HSP70,and HSP90 in chicken brain tissues and chicken embryonic neurocytes.In the Pb group,m RNA expression of HSP40 and HSP60 in gray matters increased with the increase of time,HSP70 mRNA expression in brainstem increased with the increase of time,and had time effects.Se alleviated Pb-induced expression of HSPs in chicken brain tissues and embryonic neurocytes.(5)Pb inhibited Bcl-2 m RNA expression in chicken brain tissues and chicken embryonic neurons,Bcl-2 protein expression in brain white matters and embryonic neurocytes;and induced m RNA expression of p53,Bax,Cyt c and Caspase-3 in chicken brain tissues and embryonic neurocytes,protein expression of p53,Bax,Cyt c and Caspase-3in brain white matters and embryonic neurocytes.In the Pb group,m RNA expression of Bax and Cyt c in cerebellums increased with the increase of time,Caspase-3 mRNA expression in brainstems increased with the increase of time,and had time effects.Se alleviated Pb-induced mRNA and proteinexpression of apoptosis-related gene(Bcl-2,p53,Bax,Cyt c,and Caspase-3)in chicken brain tissues and embryonic neurocytes.(6)Pb caused inflammatory cell infiltration and apoptosis in chicken brain tissues,induced apoptosis in chicken embryonic neurons.Se alleviated Pb-causedinflammatory cell infiltration and apoptosis in chicken brain tissues,alleviated Pb-induced apoptosis in chicken embryonic neurons.Pb induced oxidative stress,caused inflammation reaction,and induced apoptosis in chicken nervous tissues.Pb induced chicken neurotoxicity,Se has a alleviate effect on chicken neurotoxicity induced by Pb.