硒缺乏通过TLR4/MyD88/NF-κB信号通路介导鸡胸腺细胞凋亡  

Selenium Deficiency Induced Thymocytes Apoptosis of Broilers via the TLR4/MyD88/NF-κB Signaling Pathway

作　　者：张瑞莉[1,2] 张迪 郭荣[1,2] 陈阳 李广兴 黄小丹[1,2] ZHANG Ruili;ZHANG Di;GUO Rong;CHEN Yang;LI Guangxing;HUANG Xiaodan(College of Veterinary Medicine,Northeast Agricultural University,Harbin 150030,China;Heilongjiang Key Laboratory of Experimental Animals and Comparative Medicine,Harbin 150030,China)

机构地区：[1]东北农业大学动物医学院,哈尔滨150030 [2]黑龙江省实验动物与比较医学重点实验室,哈尔滨150030

出　　处：《畜牧兽医学报》2022年第11期4035-4047,共13页ACTA VETERINARIA ET ZOOTECHNICA SINICA

基　　金：国家自然科学基金青年基金项目(31602028);黑龙江省博士后基金项目(LBHQ19068)。

摘　　要：本试验旨在探讨硒缺乏是否通过激活Toll样受体信号通路诱导鸡胸腺细胞凋亡。复制硒缺乏模型,将200只1日龄健康的肉鸡随机分为对照组(C组)和缺硒组(L组),对照组饲喂硒含量0.2 mg·kg^(-1)的正常日粮,缺硒组饲喂硒含量0.004 mg·kg^(-1)的缺硒日粮。在15、25、35、45、55日龄时,每组分别选取15只鸡,观察胸腺组织病理形态变化和超微结构变化;检测胸腺组织中TLR4信号转导通路与细胞凋亡相关因子的表达。又建立了MDCC-MSB1(MSB1)细胞硒缺乏模型,并在此基础上设立6个分组:对照(C group)组、缺硒(L group)组、缺硒+转染空质粒(L+pCMV-HA-N)组、缺硒+siRNA阴性对照(L+NCsiRNA)组和缺硒+过表达TLR4(L+pCMV-HA-TLR4)组、缺硒+干扰TLR4(L+siChTLR4)组,低硒处理5 d后,检测细胞活力、细胞凋亡情况、TLR4信号转导通路与细胞凋亡相关因子的表达。结果显示:1)与C组相比,L组皮质髓质的淋巴细胞数量减少、细胞排列紊乱、皮质髓质充血、核碎裂,广泛的局灶性坏死。L组鸡胸腺组织淋巴细胞间出现裂隙,体积缩小,细胞碎裂,核染色质边集,线粒体肿胀,嵴断裂。2)与15日龄C组相比,L组鸡胸腺中TLR4、MyD88、NF-κB、Caspase-3、Caspase-9、Bax mRNA和蛋白表达水平在15~55日龄中均显著上调,Bcl-2 mRNA和蛋白表达水平呈相反趋势。3)与C组相比,L组MSB1细胞活力显著下降、细胞凋亡数量明显增加、TLR4、MyD88、NF-κB、Caspase-3、Caspase-9、Bax mRNA和蛋白的表达均显著增加、Bcl-2 mRNA和蛋白表达水平极显著降低;与L组相比,L+siChTLR4组细胞活力明显增强、细胞凋亡数量明显减少、相关因子mRNA和蛋白表达显著下降,而L+pCMV-HA-TLR4组细胞活力明显降低、细胞凋亡数量明显增加、相关因子mRNA和蛋白表达均明显增加。综上所述,硒缺乏通过TLR4/MyD88/NF-κB信号通路介导鸡胸腺细胞凋亡,并进一步诱导鸡胸腺损伤。This study aimed to investigate whether selenium deficiency induced apoptosis of chicken thymocytes by activating toll-like receptor signaling pathway.In vivo experiment,200 healthy one-day-old broilers were randomly divided into control group(C group) and selenium deficiency group(L group) by replicating selenium deficiency model,the control group was fed a normal diet with 0.2 mg·kg^(-1) selenium,and the se-deficient group was fed a se-deficient diet with 0.004 mg·kg^(-1) selenium.At 15,25,35,45,and 55 days of age,15 chicks were selected from each group,the morphological and ultrastructural changes of thymus tissue were observed.TLR4 signaling pathway and apoptosis-related factors were detected in thymus tissue.The selenium deficiency model of MDCC-MSB1(MSB1) cells in vitro was established,and six groups were established on this basis:Control(C) group,Selenium deficiency(L) group,selenium deficiency+transfection empty plasmid(L+pCMV-HA-N) group,selenium deficiency+siRNA negative control(L+ NCsiRNA) group,selenium deficiency + overexpression of TLR4(L+ pCMV-HA-TLR4) group,selenium deficiency +siChTLR4(L+ siChTLR4) group.After 5 days of low selenium treatment,cell viability,apoptosis,TLR4 signal transduction pathway and expression of apoptosis-related factors were detected.Results were as follows:1) Compared with the C group,the number of lymphocytes in the medulla of the cortex in the L group was reduced,the cells were disordered,the medulla of the cortex was hyperemic,the nucleus was fragmented,and extensive focal necrosis was observed.The thymus tissue of chickens in L group showed fissure,reduced volume,cell fragmentation,and nuclear chromatin edge aggregation,mitochondrial swelling,cristae fracture;2) Compared with C group at 15 days of age,mRNA and protein expressions of TLR4,MyD88,NF-κB,Caspase-3,Caspase-9 and Bax in the thymus of L group were up-regulated at 15 to 55 days of age,the expression levels of Bcl-2 mRNA and protein showed opposite trends;3) Compared with C group,the viability of MSB1 cells i

关 键 词：硒缺乏 TLR4 MYD88 NF-ΚB 胸腺 凋亡 

分 类 号：S852.3[农业科学—基础兽医学]