Maternal obesity is associated with a wide spectrum of delivery disorders, such as delayed or post-term delivery, that might be explained partly by the increase in plasma leptin levels in obese women, as leptin inhibits in vitro myometrial contractility. Delivery involves uterine apoptosis and remodelling of the extracellular matrix, via the activation of matrix metalloproteinases (MMP). This study was aimed to assess the role of leptin on human myometrium, by studying the interaction of leptin with lipopolysaccharide (LPS)-induced apoptosis and degradation of myometrial collagen.Myometrial biopsies were obtained from women undergoing caesarean delivery before labour onset. The effects of leptin on myometrial apoptosis and remodelling were assessed by incubating the strips for 48h with LPS (10 µg/ml) alone or with leptin (from 10-10 to 10-8 M).Leptin prevented LPS-induced apoptosis, in a concentration-dependent manner, by down-regulating cleaved caspase-3, BAX and up-regulating BCL2 expression. This effect was specifically mediated through leptin receptors stimulation followed by ERK1/2 signalling pathway activation. Leptin prevented, in a concentration-dependent manner, an LPS-induced decrease in myometrial collagen content, and this effect was associated with a decrease in MMP2 and MMP9 activity and overexpression. These effects of leptin were abolished by pre-treatment with a selective leptin receptor antagonist. These results suggest new potential pathways involved in delivery disorders of obese women and propose a role for leptin-induced inhibition of myometrial apoptosis and extracellular matrix remodelling in the development of such disorders.
