PCV2感染仔猪急性期蛋白的变化

Changes of Acute Phase Proteins Profile in PCV2 Experimentally Infected Piglets

【目的】探讨实验性感染PCV2仔猪血清中急性期蛋白浓度和肝脏急性期蛋白表达的变化,为PCV2的致病机制和诊断提供有价值的资料。【方法】19头ELISA检测PCV2抗体阴性的5周龄健康断奶仔猪,随机分为对照组和攻毒组,在攻毒后不同时间采集血液和肝脏。用ELISA方法检测血清中APPs的动态变化,荧光定量RT-PCR测定肝脏中APPsmRNA表达,同时观察肝脏的组织病理学变化。【结果】仔猪接种PCV2后,肝脏出现实质细胞变性,结缔组织增生和嗜酸性粒细胞浸润为特征的病理学损伤;血清中,猪主要急性期蛋白(Pig-MAP)在攻毒后7d达到峰值,在7和10d显著高于对照组(P<0.05);血清淀粉样蛋白A(SAA)在攻毒后7d和21d显著高于对照组(P<0.05);血清载脂蛋白AⅠ(Apo-AⅠ)攻毒后21d显著高于对照组(P<0.05),其余时间差异均不显著;PCV2感染后21d仔猪肝脏中结合珠蛋白(HP)、C-反应蛋白(CRP)、α1-酸性糖蛋白(AGP)和SAAmRNA的表达呈现升高的趋势。【结论】PCV2感染可引起仔猪肝脏出现以实质细胞变性坏死和结缔组织增生为特征的病理学变化,血清APPs浓度和肝脏APPsmRNA表达呈现不同的变化,其中Pig-MAP可以作为病程发展的重要检测指标,对监测PCV2感染、疾病的预后起重要作用。

Objective In order to obtain the valuable evidence of pathogenic mechanism and clinical diagnosis about PCV2 infection,the dynamic changes of acute phase proteins（APPs） concentration in serum and APPs expression in liver were studied in piglets infected with PCV2.MethodNineteen conventional piglets without antibodies against PCV2,obtained from a farrow-to-finish farm and certified as having a health status,were divided into control group and challenge group,at randomly.Their blood and liver tissues were collected at different days post-inoculation（DPI） of PCV2.The dynamic changes in concentration of APPs were detected by ELISA,and its mRNA expression in liver were evaluated using fluorescence quantitative RT-PCR,respectively.The histopathological changes of liver lesions were also observed.Result After PCV2 infection,there were variable degrees of pathological lesions of parenchymal cells in livers,vacuolar degeneration in hepatocytes,proliferation of connective tissue in perilobuler area,and variable degrees of eosinophilic granulocyte infiltration in the perilobular and parenchymal area.The maximum values of pig-main acute phase protein（pig-MAP） were reached on 7 DPI,a significant increase with respect to the serum concentrations before infection（0 DPI）（P0.05）,and the values were gradually recovered to baseline after 14 DPI.Serum amyloid A（SAA） concentration had a significant increase on 7 and 21 DPI compared to the pre-infection（P0.05）.Apolipoprotein-AⅠ（ApoA-Ⅰ） was significantly increased on 21 DPI（P0.05）.There was an increasable tendency of haptoglobin（HP）,C-reactive protein（CRP）,alpha-1 acid glycoprotein（AGP） and SAA mRNA on 21 DPI.Conclusion The main histopathological lesions of liver were hepatocytes degeneration and necrosis,connective tissue proliferation in piglets infected with PCV2.The APPs showed different levels in concentration in serum and expression profile in livers.Among them,Pig-MAP could be a valuable marker for monitoring the course of PCV2 infection and prognosis.