Effects of Subcutaneous LPS Injection on Gestational Length and Intrauterine and Neonatal Mortality in Mice

Abstract

Background: Infection during pregnancy can predispose offspring to develop various psychiatric disorders such as depression in later life. In order to investigate the potential mechanisms underlying these associations, animal models of maternal infection have been employed. As such, lipopolysaccharide (LPS) has been commonly used to mimic a bacterial infection in pregnant mice. Objective: The original aim of our study was to investigate the effects of different doses of subcutaneous LPS administration on affective behavior in adult mouse offspring. In the present paper, however, we report that subcutaneous LPS administration has a profound impact on gestational length, litter size, and perinatal mortality in the offspring, even at a relatively low dose. Methods: Pregnant mice were randomly divided into 3 groups, receiving either a high (2 mg/kg) or a low (0.5 mg/kg) dose of LPS or phosphate-buffered saline by means of subcutaneous injection. Subsequently, the effects on gestational length, litter size, and perinatal mortality in the offspring were assessed. Results: After subcutaneous injection with a high dose of LPS, we observed a significant decrease in gestational length and an increase in neonatal mortality. When the low dose was administered, a tendency towards a reduced litter size was observed, most likely reflecting increased intrauterine mortality in response to prenatal maternal LPS exposure. Conclusions: We showed that subcutaneous administration of 2 mg/kg LPS to pregnant mice in the last phase of gestation should be avoided because of high offspring mortality rates, whereas subcutaneous injection of 0.5 mg/kg LPS seems to result in reabsorption of the fetuses.

Partial protective effects of melatonin on developing brain in a rat model of chorioamnionitis

“…The number of pregnant females treated in each experimental group was planned according to the number of pups required for each experiment to reach statistical threshold, i.e., seven pups per group for optical density and five pups per group for immunofluorescence experiments. As over mortality were previously observed in pregnant rats and fetuses treated by LPS, two times more female rats were treated with LPS and LPS plus melatonin 47 , 48 . Treatments were randomly assigned to female rats.…”

Macrophage Migration Inhibitory Factor in Acute Adipose Tissue Inflammation

“…To underscore our in vitro observations, we investigated the accumulation of labeled macrophages into LPS-injected epididymal fat pads of WT and Mif –/– mice. LPS was used as a stimulus to produce local adipose tissue inflammation [ 32 , 33 ]. Mif –/– mice showed a significantly lower infiltration rate of FITC-labeled macrophages when compared to WT mice which confirms the potential importance of MIF in cell recruitment to acutely inflamed adipose tissue.…”