Introduction: Lansoprazole is one of the proton pump inhibitor drugs widely used in the treatment of gastro-duodenal ulcers and disorders. However, there is not enough data about unexplored adverse effects of lansoprazole on the integrity of the placental barrier. Therefore, the present study was conducted to determine whether placental structure could be affected by lansoprazole administration.

Materials and methods: A total of 24 pregnant Balb/C mice were randomly divided into one control and three experiment groups (n=6).The experimental animals were given 25, 50 and 100 mg/kg of lansoprazole intraperitoneally on days 6-16 of pregnancy. At the end point and on the day 17 of gestation all animals were sacrificed. Then, the placentas specimens were taken and processed for histological examinations. Histological sections were stained with hematoxylin-eosin and were examined under light microscopy.

Results: The histological examinations showed remarkable cellular changes in the placenta after treatment with lansoprazole. The placentas from drug administrated mice exhibited conspicuous decrease in the spongy layers size when compared with controls. Also, both polymorph and mononuclear cell infiltration into placental parenchyma were seen in the animals treated with 100 mg/kg lansoprazole. In addition, dilation of the intervillous space, massive vasculature congestion, increased giant cell population and fibroblastic proliferation were seen in the placental tissues from experimental groups.