CAJ | 학술논문

本试验旨在研究脂多糖（ LPS）刺激对仔猪下丘脑-垂体-肾上腺（ HPA）轴Toll样受体4（ TLR4）信号通路关键基因表达的影响。选取12头断奶仔猪，分成2个组，每个组6个重复。试验组注射100μg/kg体重的LPS，对照组注射等量的生理盐水。注射LPS或生理盐水4 h后采血，测定血浆中与应激相关激素的含量；采血后屠宰仔猪，取下丘脑、垂体、肾上腺，测定TLR4信号通路关键基因的mRNA表达水平，包括TLR4、髓样分化因子88（ MyD88）、白细胞介素-1受体相关激酶1（ IRAK1）、肿瘤坏死因子受体相关因子6（ TRAF6）和核转录因子-κB （ NF-κB ） mRNA表达水平。结果表明：与对照组相比，1） LPS刺激导致血浆肿瘤坏死因子-α、皮质醇和促肾上腺皮质激素含量显著上升（ P＜0．05）。2） LPS刺激导致TLR4信号通路关键基因TLR4在下丘脑、垂体、肾上腺中mRNA表达水平显著升高（ P＜0．05）；MyD88在垂体、肾上腺中mRNA表达水平显著升高（P＜0．05），在下丘脑中mRNA表达水平有升高的趋势（P＜0．10）；IRAK1在垂体、肾上腺中mRNA表达水平有升高的趋势（P＜0．10）；TRAF6在下丘脑、垂体、肾上腺中mRNA表达水平显著升高（P＜0．05）；NF-κB在垂体中mRNA表达水平显著升高（P＜0．05）。试验结果表明LPS刺激激活了HPA轴，诱导了HPA轴的TLR4信号通路关键基因的表达。
본시험지재연구지다당（ LPS）자격대자저하구뇌-수체-신상선（ HPA）축Toll양수체4（ TLR4）신호통로관건기인표체적영향。선취12두단내자저，분성2개조，매개조6개중복。시험조주사100μg/kg체중적LPS，대조조주사등량적생리염수。주사LPS혹생리염수4 h후채혈，측정혈장중여응격상관격소적함량；채혈후도재자저，취하구뇌、수체、신상선，측정TLR4신호통로관건기인적mRNA표체수평，포괄TLR4、수양분화인자88（ MyD88）、백세포개소-1수체상관격매1（ IRAK1）、종류배사인자수체상관인자6（ TRAF6）화핵전록인자-κB （ NF-κB ） mRNA표체수평。결과표명：여대조조상비，1） LPS자격도치혈장종류배사인자-α、피질순화촉신상선피질격소함량현저상승（ P＜0．05）。2） LPS자격도치TLR4신호통로관건기인TLR4재하구뇌、수체、신상선중mRNA표체수평현저승고（ P＜0．05）；MyD88재수체、신상선중mRNA표체수평현저승고（P＜0．05），재하구뇌중mRNA표체수평유승고적추세（P＜0．10）；IRAK1재수체、신상선중mRNA표체수평유승고적추세（P＜0．10）；TRAF6재하구뇌、수체、신상선중mRNA표체수평현저승고（P＜0．05）；NF-κB재수체중mRNA표체수평현저승고（P＜0．05）。시험결과표명LPS자격격활료HPA축，유도료HPA축적TLR4신호통로관건기인적표체。
This experiment was conducted to investigate the effects of lipopolysaccharide ( LPS) challenge on the expression of the key genes in toll-like receptor 4 ( TLR4) signaling pathway of hypothalamic-pituitary-ad-renal ( HPA) axis of piglets. Twelve weaner piglets were allotted to two groups ( 6 replicates per group and 1 piglet per replicate) . The piglets in the experimental group were injected with 100 μg/kg body weight LPS, whereas the piglets in the control group were injected with an equivalent amount of sterile saline. At 4 h post-challenge, blood samples were collected for determining stress-related hormones contents in the plasma. Fol-lowing blood collection at 4 h, the piglets were slaughtered, and hypothalamus, pituitary gland and adrenal gland were collected. The mRNA expression levels of the key genes in TLR4 signaling pathway, including TLR4, myeloid differentiation factor 88 ( MyD88) , IL-1 receptor-associated kinase 1 ( IRAK1) , tumor necro-sis factor receptor-associated factor 6 ( TRAF6) and nuclear factor-κB ( NF-κB) in HPA axis, were detected by real-time quantitative PCR. The results showed as follows: compared with control group, 1) LPS signifi-cantly increased plasma TNF-α, cortisol and adrenocorticotropin contents ( P<0.05) . 2) After LPS challenge, TLR4 mRNA expression level was significantly increased in hypothalamus, pituitary gland and adrenal gland (P<0.05). MyD88 mRNA expression level was significantly increased in pituitary gland and adrenal gland ( P<0.05) . The mRNA expression level of MyD88 in the hypothalamus had a tendency to increase ( P<0.10) . IRAK1 mRNA expression level in pituitary gland and adrenal gland had a tendency to increase ( P<0. 10 ) . TRAF6 mRNA expression level was significantly increased in hypothalamus, pituitary gland and adrenal gland ( P<0.05) . NF-κB mRNA expression level was significantly increased in pituitary gland ( P<0.05) . These re-sults indicate that LPS challenge actives HPA axis and induces the mRNA expression levels of the key genes in TLR4 signaling pathway of HPA axis.