Expression of TP0155 mRNA in rabbits with early infection of Treponema pallidum / 中华临床感染病杂志

ABSTRACT

Objective To investigate the expression of TP 0155 mRNA in rabbits with early infection of Treponema pallidum ( T.pallidum ). Methods Three New Zealand white rabbits were subcutaneously injected with T.pallidum Nichols Seattle strains.Each rabbit was inoculated at ten sites with 106 T.pallidum/site.Skin lesions at the primary stage of syphilis were observed at different time points. Biopsy from one of the lesions was obtained from each rabbit every three days for detection of TP 0155 mRNA and house keeping gene TP 0574 mRNA.TP0155 plasmid standard was constructed by molecular cloning technique , and the quantitative PCR was used to continuously detect the expression of TP 0155 mRNA and TP0574 mRNA from lesion at different time points.Kruskal Wallis test and Bonferroni method were used to analyze the data.Results On d6, red papules appeared on the dorsal skins of rabbits ,there were ulcers in the center of the lesions on d19,presenting typical appearance of syphilis chancre.On d24 the scab of ulcer became smaller; on d25 the rabbits showed disseminated secondary syphilis , which became smaller and disappeared on d30.The copy numbers of TP0155 plasmid standards were 7.48 ×109 copies/μL.There were significant differences in expression of both TP 0155 mRNA and TP0574 mRNA at different time points (χ2 =32.756 and 52.344,both P<0.01).The expression levels of TP0155 mRNA and TP0574 mRNA increased in the early stage, and both reached the peak at d15 (both P<0.05), and then rapidly declined. There were significant differences in normalized TP 0155 mRNA ( TP0155 ×1000/TP0574 mRNA ) at different time points(χ2 =19.758,P<0.05),which reached the peak on d24 and d30,respectively (all P<0.05).Conclusion The level of TP0155 mRNA increases with the disappearance of chancre and secondary syphilis lesions , suggesting that TP0155 might be involved in immune escape of T.pallidum.