Objective:To explore the effect of ceftiaxone sodium administered by amniocentesis on chorioamnionitis and trophoblast apoptopsis in treatment of intrauterine infection with Escherichia coli(E coli)in late pregnant SD rats.Methods:36 SD pregnant rats for 15 days were randomly divided into four groups(9 in each)

intrauterine admistration(IUA)group and control(IUC)group

maternal intravenous injection(IVA)group and control(IVC)group.0.2 ml E coli suspension at a dose of 1010/L was inoculated into one horn of uterus of each rat on 15-day of pregnancy.On the 16-day of pregnancy

each gestational sac in inoculation side of rats in IUA group and IUC group was given ceftriaxone sodium or appropriate volume of isotonic Na chloride(NS)by amniocentesis

and each rat in IVA group and IVC group was given ceftiaxone sodium or appropriate volume of isotonic NS intravenously.From the 17th day

3 rats in each group were sacrificed randomly and respectively everyday.The top 3 sacs in inoculation side of each rat were detected

placenta and membrane was get for histological analysis with light microscope by HE staining to compare Naeye’s stage and grade of chorioamnionitis.One of the top 3 sacs in inoculation side of each rat was randomly selected.The apoptosis of trophoblasts was semiquantitatively analyzed by TUNEL staining.Results:The mild chorioamnionitis rates were higher in total and each day administration group of amniocentesis route

in total and late 2 days administration group of intravenous route

and in total and 1st day amniocentesis route group of two administration groups(P<0.05).The apoptosis level of trophoblasts in administration groups was lower than in control groups(P<0.05).The level was lower in IUA group than in IVA group on the 1st and 3rd after administration(P<0.05).Conclusion:Ceftriaxone sodium administered with a single dose by amniocentesis compared with maternal intravenous injection is the more effective treatment for intrauterine infection with E coli in late pregnant SD rats

which releases chorioamnionitis more quickly

suppresses and postpones the inflammation induced apoptosis of trophoblasts

thus improves the pregnancy outcome.