Establishment of a mouse model for genital tract infection with different serovars of Chlamydia trachomatis

Abstract

Objective To establish a mouse model for genital tract infection with different serovars of Chlamydia trachomatis (Ct),and to provide a basis for understanding the relationship between Ct serovars and virulence.Methods Six-week-old female BALB/c mice were divided into 4 groups:study group (pretreated with progesterone and inoculated with 4.0 × 107 inclusion-forming units (IFU) of Ct serovar E,F,J and K,respectively),progesterone-control group (pretreated with progesterone and inoculated with culture medium of McCoy cells),non progesterone-control group (inoculated with 4.0 × 107 IFU of Ct serovar F),blank control group receiving no treatment.At 4 and 7 days after the inoculation,the appearance of vulva was observed,vaginal swab specimens were obtained and subjected to cell culture,direct immunofluorescence assay and real-time fluorescence-based PCR for the detection of Ct.Results A slight inflammation of the genital tract was observed in the mice 4 days after the inoculation with Ct serovar E,F,J or K in the study group.Cell culture,direct immunofluorescence assay and real-time fluorescence-based PCR all confirmed that Ct was present in vaginal specimens from the study group,but absent from the control groups.The longest duration of infection was 21 days in 1 out of 11 mice inoculated with Ct serovar K,followed by 17 days in 1 out of 11 mice inoculated with Ct serovar J,14 days in 5 out of 11 mice with Ct serovar F and in 2 out of 11 mice with Ct serovar K.Conclusion The model for genital tract infection with different serovars of Ct can be established in mice at a right age bypretreatment with progesterone and inoculation with a certain amount of Ct. Key words: Chlamydia trachomatis; Mice; Models, animal