Study On The Pathogenicity Of Ureaplasma Urealyticum Serotype 3 With Different Concentration In Murine Model

Objective: To study the pathogenicity of Ureaplasma urealyticum serotype 3 (Uu3) with differrent concentration in murine model.Method: 156 oestradiol-treated mice were randomly divided into 4 groups, including groupA, B, C and D.Ureaplasma urealyticum serotype 3 with the concentration of 10~7copy/g (group A), 10~6copy/g (groupB),10~5copy/g (groupC) were inoculated intravaginally into all 48 mice of every group ,while 12 mice of control group (groupD) inoculated sterile medium. They were necropsied at 1,3,7,14, 21,35 days of postinoculation randomly,to detect Uu3 from cervical secretions by fluorescent quantitative polymerase chain reaction (FQ-PCR), observing tissues of cervix, endometria,fallopian tube by light microscope and cervical mucosa by scanning electron microscope.Result: (1)The total positive rates of Uu3 in three experimental groups showed a significant difference(P=0.000), which were 62.5% (30/48), 50.0%(24/48), 16.7%(8/48).And the positive rate descended as the days of postinoculation lasting. The highest positive rates of three experimental groups were 100.0%(8/8), 87.5%(7/8), 37.5%(3/8)at 1d after inoculation,but the conlisation didn't persist at 35d.All mice of control group were negtive.(2)There was statistical difference in the quantity of Uu3 among experimental groups,the higher inocula of Uu3 , the higher quantity conlisation. Their peak level were 1.70×10~7copy/g, 3.75×10~6copy/g, 1.45×10~5copy/g reached at 1d,but the FQ-PCR values reduced as the days of postinoculation lasting.(3)The total pathogenicity rates of three groups were significant different at 7～35d ,which were 56.3 %(18/32), 43.8%(14/32), 6.3%(2/32), P=0.000.And groupA, groupB were significant higher than groupC at all time points. None of control group was positive.Conclusion:(1) The positive rate , quantity and pathogenity rate among experimental groups are increased with the higher concentration of Uu3 inoculated in murine model.(2)In murine model, the pathogenicity of Uu3 varies with the quantity conlisation in genital tract. when Uu3 FQ-PCR value is≥10~6copy/g,it will cause to disease easily.