Effects of intrauterine infection in different periods on the placenta and endometrial blood vessel formation of pregnant mice and the growth and development of fetal rats

Abstract

Objective: To investigate the effects of intrauterine infection in different periods on the placenta and endometrial blood vessel\xa0formation of pregnant rats and the growth and development of fetal rats.Methods: According to the random number table method, 32 pregnant rats were divided into the early infection group, the\xa0mid-term infection group, the late infection group and the control group, with 8 rats in each group. On the\xa03rd, 9th and 15th day of pregnancy, lipopolysaccharide was injected intraperitoneally to construct intrauterine infection models. The pregnant rats\xa0in the control group were intraperitoneally injected with the same dose of 0.9% sodium chloride solution. On the\xa018th day of\xa0pregnancy, the inflammatory factors [interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α)], the blood vessel density of placenta\xa0and endometrium in the placental tissues of pregnant rats, dead fetus + absorbed fetus, the inflammatory factors IL-6, TNF-α and\xa0oxidation reaction indicators [malondialdehyde (MDA) and myeloperoxidase (MPO)] in the fetal rat lung and brain tissues were\xa0detected.Results: The changing trend of IL-6 and TNF-α levels in the placental tissues of pregnant rats with intrauterine infection in\xa0different periods was: the control group < the late infection group < the mid-term infection group < the early infection group, the\xa0differences were statistically significant (p <.05). The changing trend of fetal rat weight, placental weight and placental coefficient\xa0in the intrauterine infection groups in different periods was: the control group > the late infection group > the mid-term infection\xa0group > the early infection group, the differences were statistically significant (p < .05). The blood vessel density of placenta and\xa0endometrium, the mean number of fetuses, brain coefficient and lung coefficient in the late infection group were significantly\xa0increased in comparison with the early infection group and the mid-term infection group. The total number and the ratio of dead\xa0fetus + absorbed fetus, the levels of IL-6, TNF-α, MDA and MPO in brain and lung tissues were significantly reduced, and\xa0the differences were statistically significant (p < .05). The blood vessel density of placenta and endometrium, brain coefficient\xa0and lung coefficient of pregnant rats in the mid-term infection group were significantly increased in comparison with the early\xa0infection group, and the differences were statistically significant (p < .05). There was no statistically significant difference in the\xa0other indicators between the two groups (p > .05).Conclusions:\xa0Intrauterine infection in different periods can inhibit placental and endometrial angiogenesis, and affect the survival rate of fetal rats and the growth and development of brain and lung. The reason may be related to the aggravation of fetal\xa0inflammatory responses and oxidative stress. The earlier the intrauterine infection occurs, the severer the adverse effects on the\xa0fetal rats will be.