title: Lower expression of inducible nitric oxide synthase and higher expression of arginase in rat alveolar macrophages are linked to their susceptibility to Toxoplasma gondii infection.
abstract: 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.
authors.affiliation: State Key Laboratory of Biocontrol, Center for Parasitic Organisms, School of Life Sciences, Sun Yat-Sen University, Guangzhou, PR China.
authors.forename: Zhi-Jun
authors.initials: ZJ
authors.lastname: Zhao
authors.forename: Jia
authors.initials: J
authors.lastname: Zhang
authors.forename: Jun
authors.initials: J
authors.lastname: Wei
authors.forename: Zhi
authors.initials: Z
authors.lastname: Li
authors.forename: Tao
authors.initials: T
authors.lastname: Wang
authors.forename: Si-Qi
authors.initials: SQ
authors.lastname: Yi
authors.forename: Ji-Long
authors.initials: JL
authors.lastname: Shen
authors.forename: Ting-Bao
authors.initials: TB
authors.lastname: Yang
authors.forename: Geoff
authors.initials: G
authors.lastname: Hide
authors.forename: Zhao-Rong
authors.initials: ZR
authors.lastname: Lun
mesh_terms: D000818:Animals; D001119:Arginase / Q000378:metabolism*; D004198:Disease Susceptibility; D016676:Macrophages, Alveolar / Q000201:enzymology*; D009569:Nitric Oxide / Q000096:biosynthesis; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism*; D051381:Rats; D014122:Toxoplasma / Q000254:growth & development / Q000472:pathogenicity*; D014123:Toxoplasmosis / Q000201:enzymology*
chemical_list: D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; D001119:Arginase