发酵支原体、梨支原体大鼠致死性感染实验研究

Experimental study on the lethality of rats in Mycoplasma infection

目的制备发酵支原体(Mycoplasma fermentans,Mf)梨支原体(Mycoplasma pirum,Mpi)致死性感染大鼠模型。方法清洁级SD大鼠54只,分免疫抑制组(47只)与非免疫抑制组(7只)。免疫抑制组预先经环磷酰胺隔天注射(50mg/kg.d)三次制备,分别腹腔注射0.6mL三种支原体标准菌株Mf、Mpi穿通支原体(Mpe),以及本实验室分离株(W12)和无菌生理盐水;非免疫抑制组取正常大鼠腹腔注射同剂量Mf。计算各组死亡率,死亡大鼠无菌解剖,分别取大鼠血液、心、肝、肺,肾和脑组织进行再培养,进而取再培养阳性脏器进行超微结构观察。结果实验组大鼠致死率与对照组比较均有显著性差异(P<0.01);大鼠血液、心、肝、肺,肾和脑组织中支原体检出率与对照组比较均有显著性差异(P<0.01)。电镜下大鼠的心、肝、肺、肾及脑组织内见支原体,且细胞间质高度水肿,线粒体肿胀、空泡样改变,器官实质变性坏死,大量炎性细胞浸润,并以免疫抑制肺和脑最为显著。结论Mf、Mpi、Mpe、W12支原体感染的免疫抑制组大鼠死亡率明显高于非免疫抑制组,且免疫抑制组肺和脑损伤最为显著。

A model of the lethal infection in mycoplasma was established in 54 ICR rats with immunosuppression and non-immunosuppression, in which the former 47 rats were injected intraperitoneally with cyclophosphamide, 50mg/（kg·day）, every other day, and then received 0.6 mL of 3 standard strains of M.fermentans, M. pirim and M. penetrans and one strain of mycoplasma W12 isolated by our laboratory, while the latter 7 normal rats were injected with M.fermentans and physiological saline solution served as controls. The blood, liver, heart, kidney, lung and brain specimens were taken for re-cultivation of the organisms, and the organs of the young rats with mycoplasma infection were taken for further uhrastructural observation. It was found that the lethality of the experimental groups of rats showed significant differences in comparison with those of the controls（P〈0.01）. The detection of mycoplasma in blood, liver, heart, kidney and brain of the dead rats of the experimental groups also showed differences compared with controls （P〈0.01）. Under uhrastructural observation, mycoplasmas could he demonstrated in these organs of the dead rats with high degree of interstitial edema, mitochondrial crista swelling, vacuolar changes of cells and multiple damages of organs large amount of infiltration with inflammatory cells could be demonstrated, especially in brain and lungs of the immunosuppressive rats. It is evident that the lethal infection of mycoplasmas appears to be more severe in the immunosuupressive rats than that of the non-immunosuppressive ones.