State Key Laboratory of Biocontrol, Center for Parasitic Organisms, School of Life Sciences, Sun Yat-Sen University, Guangzhou, PR China.
PLoS One. 2013 May 15;8(5):e63650. doi: 10.1371/journal.pone.0063650. Print 2013.
Rats are naturally resistant to Toxoplasma gondii infection, particularly the RH strain, while mice are not. Previous studies have demonstrated that inducible nitric oxide synthase (iNOS) and arginase-1 of rodent peritoneal macrophages are linked to the mechanism of resistance. As an increasing number of studies on human and animal infections are showing that pulmonary toxoplasmosis is one of the most severe clinical signs from T. gondii infection, we are interested to know whether T. gondii infection in alveolar macrophages of rats is also linked to the levels of iNOS and arginase-1 activity. Our results demonstrate that T. gondii could grow and proliferate in rat alveolar macrophages, both in vitro and in vivo, at levels higher than resistant rat peritoneal macrophages and at comparable levels to sensitive mouse peritoneal macrophages. Lower activity and expression levels of iNOS and higher activity and expression levels of arginase-1 in rat alveolar macrophages were found to be linked to the susceptibility of T. gondii infection in these cells. These novel findings could aid a better understanding of the pathogenesis of clinical pulmonary toxoplasmosis in humans and domestic animals.
大鼠对刚地弓形虫感染具有天然抗性，尤其是 RH 株，而小鼠则没有。先前的研究表明，啮齿动物腹膜巨噬细胞中的诱导型一氧化氮合酶（iNOS）和精氨酸酶-1与抗性机制有关。随着越来越多的关于人类和动物感染的研究表明，肺弓形虫病是由刚地弓形虫感染引起的最严重的临床症状之一，我们有兴趣了解大鼠肺泡巨噬细胞中的刚地弓形虫感染是否也与 iNOS 和精氨酸酶-1活性水平有关。我们的研究结果表明，刚地弓形虫可以在体外和体内的大鼠肺泡巨噬细胞中生长和增殖，其水平高于抗性大鼠腹膜巨噬细胞，与敏感的小鼠腹膜巨噬细胞相当。在大鼠肺泡巨噬细胞中发现 iNOS 的活性和表达水平较低，而精氨酸酶-1的活性和表达水平较高，这与这些细胞中刚地弓形虫感染的易感性有关。这些新发现有助于更好地理解人类和家畜临床肺弓形虫病的发病机制。
