Neonatal oxytocin prevents sex-specific spatial memory deficits induced by maternal separation through restoration of hippocampal synaptic plasticity in males
Neonatal oxytocin administration can prevent spatial memory deficits induced by early-life stress in male rats, but the implications for human application are not yet clear.
Where it sits
this study against the rest of the oxytocin corpusSummary and findings
This study measured the effects of neonatal oxytocin (OT) administration on spatial memory deficits induced by neonatal maternal separation (NMS) in male Sprague-Dawley rat pups. The intervention involved intraperitoneal OT injections during the neonatal period, followed by assessments of memory and synaptic plasticity in adulthood. The findings indicated that OT completely prevented spatial memory deficits in NMS males.
Abstract
<h4>Background</h4> Stress during critical developmental periods causes lasting neurobiological alterations. Rodent models like neonatal maternal separation (NMS) induce cognitive alterations, particularly spatial memory deficits. Oxytocin (OT) system has been suggested to underlie these consequences, as it is critical for neurodevelopment. This neuropeptide also promotes maternal nurturing, prevents neuroinflammation and displays anxiolytic properties. This study hypothesized that early postnatal OT administration could prevent NMS-induced memory alterations in adult rats. <h4>Methods</h4> Sprague-Dawley rat pups (both sexes, n=8-12/group) underwent NMS with concomitant intraperitoneal OT injections. At adulthood, novel object recognition and object location tasks were performed. Further investigation was conducted through ex vivo electrophysiological recordings of functional plasticity at Schaffer collateral-CA1 synapses (male, n=7-12/group), alongside RT-qPCR of synaptic, GABAergic, neuro-inflammatory, and oxytocin receptor markers in dorsal CA1 (male, n=4-6/group). <h4>Results</h4> NMS induced male-specific spatial memory impairment without affecting recognition memory. Early OT completely prevented spatial memory deficits in NMS males. Electrophysiological recordings revealed that NMS suppressed CA1 long-term potentiation (LTP), and neonatal OT restored it. NMS induced transcript overexpression of neuro-inflammatory markers, GABAergic markers, and synaptic proteins in dorsal CA1. OT treatment normalized or reduced these mRNA expressions, consistent with restoration of CA1 synaptic function. <h4>Conclusion</h4> Early postnatal OT prevents NMS-induced spatial memory deficits and hippocampal LTP impairments in male rats, which is associated with normalized or reduced neuro-inflammatory and GABAergic transcript expressions. These findings establish exogenous oxytocin administration during a critical neonatal window as sufficient to prevent male-specific hippocampal dysfunction and cognitive deficits induced by early-life stress, identifying the oxytocinergic system as a promising target for early neuroprotective interventions.