PCR-based evaluation of prednisolone-induced relapse of asymptomatic Toxoplasma gondii infection and therapeutic efficacy of azithromycin / 中国血吸虫病防治杂志

ABSTRACT

Objective To investigate the PCR-based evaluation of prednisolone-induced relapse of asymptomatic Toxoplasma gondii infection and the therapeutic efficacy of azithromycin.Methods A total of 36 of female ICR mice,about 20 g,were randomly divided into 6 groupscontrast group (C),prednisolone group (P),infection group(I),infection plus prednisolone group (IP),infection plus azithromycin group(IA),infection plus prednisolone and azithromycin group (IPA).The infection group (I),infection plus prednisolone group(IP),infection plus azithromycin group(IA),infection plus prednisolone and azithromycin group (IPA)were challenged at week 0 with 10 cysts of Toxoplasma gondii Prugniaud strain per injection intraperitoneally.The prcdnisolone group (P),infection plus prednisolone group (IP) infection plus prednisolone and azithromycin group (IPA)were injectied with prednisolone 1 mg into hind medial subcutaneous every day from the 6th week to 7th week.The infection plus azithromycin group(IA),infection plus prednisolone and azithromycin group (IPA) were injectied with azithromycin 250 mg/kg intraperitoneally every day from the 6th week to 7th week.The serum samples were collected and DNAs extracted at week 0,1,2,3,4,5,6 and 7 for amplification of Toxoplasma gondii of specific B1 gene by PCR.All the mice were sacrificed 7 weeks after the challenge to calculate the number of cysts in brain tissues.Results Compared with the primer of AF146527 gene,the primer of B1 gene was more sensitive and specific.The method of PCR could amplify the productions of specific B1 gene Toxoplasma gondii 5 weeks before the challenge,while it could not amplified 5 weeks after the challenge.All the mice of the IP group were dead 2 weeks after the injection of prednisolone (week 7),and the only two mice of the IPA group were dead at the same time (P <0.05),respectively.Compared with the I group,IA group and IPZ group,the number of cysts in brain tissues of the IP group significantly increased (P <0.01).Conclusions B1 as target gene is more suitable for diagnosis of Toxoplasma gondii infection by PCR.Prednisolone could induce the relapse of asymptomatic Toxoplasma gondii infection of mice and the mice are finally dead.Azithromycin is effective but it can not completely cure the Toxoplasma gondii infection.