Some studies have shown the toxic effects of enrofloxacin in various tissues. Thus, the hypothesis that enrofloxacin could interfere with placental development and generate adverse effects to the fetus was tested in this study. Enrofloxacin (Baytril(r)) was administered in the dose of 5mg/kg daily, i.m., throughout gestation in rats. The placentas were analyzed morphologically, morphometrically, and immunohistochemically on the 7, 14, and 20th days of pregnancy. The results showed that enrofloxacin reduced the number of implantation sites, weight, and placental disk total area at 14 and 20 days of development, in addition to the element components of the placenta. The histochemical analysis did not reveal significant changes in the content of collagen, reticular, and elastic fibers. The TUNEL test showed apoptosis only in placenta development at 14 days in both groups and more intense in the treated group. Head, trunk, and limb malformations were not observed in the neonates. A significant reduction in the number and weight of neonates were observed in the treated group, however, without affecting their length. Thus, it was concluded that the administration of enrofloxacin, at the dosage of 5 mg/kg during pregnancy in rats, interferes in the number of implanted embryos and placental development. This suggests caution in the administration of enrofloxacin during pregnancy because continuous exposure to this antibiotic may have adverse effects, reducing the number and weight of the offspring.
enrofloxacin; pregnancy; placental development; immunohistochemistry; reproduction