猪气喘病实验猪模型的建立

The establishment of an experimental swine model of swine mycoplasma pneumonia

目的研究建立猪气喘病人工发病模型。方法将分离得到的一株猪肺炎支原体(Mycoplasma hyopneumoniae,Mhp)Js株进行各种试验鉴定,证实其为Mhp强毒株。每头猪肺内接种Js株培养物2ml,15～25d后观察临床症状和病理变化,采集病变组织,经冻干制成攻毒用组织毒。安检合格,批号为20000324。给15头小梅山二元杂交猪分别气管内注射以KM_2培养基作10^(-2)、10^(-3)、10^(-4)和10^(-5)稀释的强毒,每头猪5ml,对照组注射培养基。攻毒后25d观察试验猪临诊症状,X线透视,记录病理变化。结果10^(-2)、10^(-3)、10^(-4)稀释的强毒试验组猪均出现了典型的猪气喘病临床症状和病理变化。结论人工发病试验测得Mhp Js株组织强毒接种气管内注射最小发病剂量为10^(-4)稀释5ml,正式试验人工发病可用100个最小发病剂量即强毒冻干物1:100稀释气管内注射5ml,可确保攻毒成功。

Objective The present study was designed to establish a model of mycoplasma pneumonia of swine （IMPS） by artificial challenge.Methods Mycoplasma hyopneumoniae Js strain was isolated and identified by biochemical and serological assays. MPS negative pigs were inoculated with 2ml of Mycoplasma hyopneumoniae Js strain culture by direct lung inoculation. The pigs were observed daily for 15 to 20 days post-inoculation for clinical symptoms and pathological changes. Infected tissues with live Mycoplasma hyopneumoniae virulent strain were lyophilized and used as the master seed for animal challenge, Artificial challenge was performed by delivering 5ml of lyophilized pathological tissues, intratracheally, into 15 Meishan pigs. The lyophilized pathological tissues used for challenge were diluted by 10^-2,10^-3, 10^-4 fold in KM2 culture medium, and pigs in the control group were inoculated with 5 ml KM2 culture medium. Clinical symptoms, pathological changes and lung X-ray results were observed twenty-five days post challenge.Results Typical clinical symptoms and pathological changes associated with MPS were observed in all pigs intratracheally inoculated with lyophilized pathological tissues that were diluted in KM2 culture medium. Therefore,5 ml of the 10^-4 dilution of lyophilized pathological tissues with Mycoplasma hyopneumoniae Js strain was the minimum dose required to induce MPS in an artificial challenge model. Conclusion The artificial challenge model of MPS could be estabhshed by intratracheally inoculation of 5ml of a 10^-2 dilution of lyophilized pathological tissues infected with the Mycoplasma hyopneumoniae Js strain.