Oxytocin alters cell fate selection of rat neural progenitor cells in vitro.

Arvind Palanisamy,Deborah J Culley,Audrey Martino,Ramaswamy Kannappan,Zhiqiang Xu,Justin D Boyd,Gregory Crosby,Matthew B Friese,Huafeng Wei

doi:10.1371/journal.pone.0191160

Abstract

Synthetic oxytocin (sOT) is widely used during labor, yet little is known about its effects on fetal brain development despite evidence that it reaches the fetal circulation. Here, we tested the hypothesis that sOT would affect early neurodevelopment by investigating its effects on neural progenitor cells (NPC) from embryonic day 14 rat pups. NPCs expressed the oxytocin receptor (OXTR), which was downregulated by 45% upon prolonged treatment with sOT. Next, we examined the effects of sOT on NPC death, apoptosis, proliferation, and differentiation using antibodies to NeuN (neurons), Olig2 (oligodendrocytes), and GFAP (astrocytes). Treated NPCs were analysed with unbiased high-throughput immunocytochemistry. Neither 6 nor 24 h exposure to 100 pM or 100 nM sOT had an effect on viability as assessed by PI or CC-3 immunocytochemistry. Similarly, sOT had negligible effect on NPC proliferation, except that the overall rate of NPC proliferation was higher in the 24 h compared to the 6 h group regardless of sOT exposure. The most significant finding was that sOT exposure caused NPCs to select a predominantly neuronal lineage, along with a concomitant decrease in glial cells. Collectively, our data suggest that perinatal exposure to sOT can have neurodevelopmental consequences for the fetus, and support the need for in vivo anatomical and behavioral studies in offspring exposed to sOT in utero.

Highlights

Synthetic oxytocin, marketed in the United States as Pitocin1, is widely used for either induction and/or augmentation of labor, and to prevent postpartum haemorrhage
In situ hybridization histochemistry reveals that oxytocin receptor (OXTR) mRNA is present in rat brain as early as embryonic day 13 (E13)[4] and binding studies show OXTRs in mouse brain by E18.5.[5]. Likewise, binding studies show OXTRs in the posterior dorsal neural tube of fetal rats at E14 [6] and on cultured astroglial cells isolated from E16 rat fetuses.[7]
A 6 h exposure to Synthetic oxytocin (sOT) had no effect on neural progenitor cells (NPC) proliferation as assessed by either ethynyl deoxyuridine (EdU) incorporation (F (2, 12) = 0.044, p = 0.96, η2 = 0.0008) or Ki-67 immunoreactivity (F (2, 12) = 0.94, p = 0.42, η2 = 0.013) (Figs 5 & 6)

Summary

Introduction

Synthetic oxytocin (sOT), marketed in the United States as Pitocin, is widely used for either induction and/or augmentation of labor, and to prevent postpartum haemorrhage. In situ hybridization histochemistry reveals that oxytocin receptor (OXTR) mRNA is present in rat brain as early as embryonic day 13 (E13)[4] and binding studies show OXTRs in mouse brain by E18.5.[5] Likewise, binding studies show OXTRs in the posterior dorsal neural tube of fetal rats at E14 [6] and on cultured astroglial cells isolated from E16 rat fetuses.[7] there is transcriptomic evidence for OXTR expression in the developing second trimester human brain (Human Brain Transcriptome Project).[8, 9] epidemiological evidence suggests an association between labor induction practices such as oxytocin and the risk of neurodevelopmental disorders.[10,11,12,13,14] Though causality has not been definitively established and there are more induced labors than children with neurodevelopmental disorders, it is plausible that sOT is one of several environmental factors that trigger or unmask underlying genetic susceptibility to neurodevelopmental disorders.[15] its contribution is unclear because the impact of maternally administered sOT on neurodevelopmental events in the fetus has not been systematically examined

Methods

Results

Discussion

Conclusion