Kim Suk, Lee Dong Soo, Watanabe Kenta, Furuoka Hidefumi, Suzuki Hiroshi, Watarai Masahisa
Department of Applied Veterinary Science, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan.
BMC Microbiol. 2005 May 4;5:22. doi: 10.1186/1471-2180-5-22.
The mechanisms of abortion induced by bacterial infection are largely unknown. In the present study, we investigated abortion induced by Brucella abortus, a causative agent of brucellosis and facultative intracellular pathogen, in a mouse model.
High rates of abortion were observed for bacterial infection on day 4.5 of gestation, but not for other days. Regardless of whether fetuses were aborted or stayed alive, the transmission of bacteria into the fetus and bacterial replication in the placenta were observed. There was a higher degree of bacterial colonization in the placenta than in other organs and many bacteria were detected in trophoblast giant cells in the placenta. Intracellular growth-defective virB4 mutant and attenuated vaccine strain S19 did not induce abortion. In the case of abortion, around day 7.5 of gestation (period of placental development), transient induction of IFN-gamma production was observed for infection by the wild type strain, but not by the virB4 mutant and S19. Neutralization of IFN-gamma, whose production was induced by infection with B. abortus, served to prevent abortion.
These results indicate that abortion induced by B. abortus infection is a result of transient IFN-gamma production during the period of placental development.
细菌感染导致流产的机制在很大程度上尚不清楚。在本研究中，我们在小鼠模型中研究了布鲁氏菌流产菌（一种布鲁氏菌病的病原体和兼性细胞内病原体）诱导的流产。
在妊娠第4.5天观察到细菌感染导致的高流产率，而其他天数则未观察到。无论胎儿是流产还是存活，均观察到细菌向胎儿的传播以及细菌在胎盘中的复制。胎盘内的细菌定植程度高于其他器官，并且在胎盘的滋养层巨细胞中检测到许多细菌。细胞内生长缺陷型virB4突变体和减毒疫苗株S19未诱导流产。在流产的情况下，在妊娠第7.5天左右（胎盘发育时期），野生型菌株感染可观察到IFN-γ产生的短暂诱导，而virB4突变体和S19则未观察到。对由流产布鲁氏菌感染诱导产生的IFN-γ进行中和可预防流产。
这些结果表明，流产布鲁氏菌感染诱导的流产是胎盘发育期间IFN-γ短暂产生的结果。
