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Constructed recombinant plasmid with CXCR2-siRNA interventions on syphilis animal experiments

Objective: To study the construction and modifications of siRNA with CXCR2 (chemokine receptor expression 2) and to evaluate its treatment effect in a rabbit animal model infected with syphilis on the testicle and eye.

Methods: The synthetic CXCR2-siRNA was linked with the pDC316-EGFP-U6 plasmid by ligase, and then this reconstruction plasmid was modified with cholesterol. After establishment of the animal model by Treponema pallidum (TP) for rabbits’ testicles and eyes, intervention by the plasmid with CXCR2- siRNA was utilized and its effects were evaluated.

Results: The recombinant plasmid was detected by agarose gel electrophoresis, and it was the right size and concentration of 285 ng/μl by UV spectrophotometer. After 28 days of treatment, there was no difference between the control group and empty plasmid control group in its treatment effect (P>0.05). However, the effect of the recombinant plasmid was obvious, with a statistical significance (P<0.01). There were significant differences between the three groups in chancre, testis swelling, orchitis, fur damage, lymphadenitis and TP in the testis by microscopy. However, there was no difference in the rabbits’ serum syphilis antibody level by the Treponema pallidum Particle Hemagglutination Assay (TPHA). EGFP (Enhanced Green Fluorescent Protein) was observed by fluorescence microscopy, and the cellular ratio with the green fluorescent protein was 10%. There was a high efficiency of transfection for the recombinant plasmid with CXCR2-siRNA.

Conclusion: The modified recombinant plasmid clearly interfered with the in vivo replication of syphilis.

Author(s): Xia Cao, Jun Ma, Zhang Liang