ABSTRACT
Objective To explore different methods for establishing animal models of Ureaplasma urealyticum ( UU) infection and to select the best method of establishment of this disease .Methods SPF female BALB/c mice and Wistar rats were multiple-infected with small dose of UU liquid or single-infected with high-dose UU liquid, pretreated with estradiol benzoate, to establish models of Ureaplasma urealyticum infection.Cervical secretion was taken for UU culture at 14, 28, 42 and 56 days after the first time UU treatment , and the reproductive organs were taken for histopathological examination.Results Gross examination of the UU-infected rats showed generally less serious lesions than the mice .The low-dose estrogen group was worst , showing hyperemia and edema , cervical hypertrophy , hydrosalpinx , enlargement , and more rigid with poor elasticity .Significant differences were observed in the vaginal UU colonization rates between the low -dose estrogen and low-dose non-estrogen groups , high-dose estrogen and non-estrogen groups , low-dose estrogen and high-dose estrogen groups, low-dose estrogen and non-estrogen groups, in both the mice and rats (P<0.05 for all).The same dose estrogen treatment caused a higher UU colonization rate in the mice than rats ( P<0.05 ) .Histological examination showed that the low-dose estrogen treated rats had no obvious pathological changes , except loose tissue edema in some rats , but apparent pathological changes were observed in the low-dose estrogen treated mice .Conclusions The vulvar lesions in the mice are worse than in the rats .Estrogen pre-treatment can increase the Ureaplasma urealyticum colonization rate in the animals.The UU colonization rate in the vagina of mice is higher than in the rats , and multiple low-dose UU treatment produces a higher UU colonization rate than a single high-dose UU treatment.Therefore, BALB/c mice are more susceptible to Ureaplasma urealyticum infection, with more serious pathological changes , and are more suitable for experimental studies of related diseases .