The Effects And Mechanism Of Maternal Separation On The Proliferation And Differentiation Of Rat Amygdaloid Oligodendrocytes

It well known that the maternal care during the early postnatal period is pivotal for brain development and mental health in adulthood,Mounting evidences have shown maternal separation(MS)during neonatal or infant period leads to deficit of the development of central nervous system and thus causes mental issues adulthood.There are numerous researches exploring the effects of MS on neuronal development,differentiation and function,however,less research was focused on the role of glial cells.In particular,recent cutting-edge studies have showed that the energy support from oligodendrocytes(OLGs)to axons is crucial for axonal survival and function,in addition to their traditional myelin-forming function.However,there is little valuable reference concerning the impacts of MS on OLG in developing brain.In the present study,we aim to study is to study the effects of MS on amygdaloid oligodendrocytes(OLGs)and the anxiety-like behavior in adult rat.We used two MS SD rats models which the rats underwent 3 or 6 hours MS per day(MS3h/MS6h)from P3 through P21.MS6 h caused significant increase of serum corticosterone accompanied with loss of OLGs in P21 and P60 Lateral nucleus(LA)and Basal nucleus(BA),while MS6 htreated rats showed significant anxiety-like behavior at P60.By contrast,MS3 h did not show any alteration in the above items compared to control rats.To further examine the underlying cause of the OLG loss at P60,we explored the proliferation,differentiation and apoptosis of OLGs,which may contribute to the alteration of OLG population,at P21 and P60.The results showed in the amygdala of MS6 h rats,the number of NG2+/Brd U+ cells was decreased at P21 and P60 with no changes in the number of NG2+/Caspase3+ cells was.We further examined the effects of corticosterone(240 ng/ml)on the m RNA expression of 11 transcription factors,mediating the regulation of OPC proliferation,differentiation,in primary OPC culture cells.we found that corticosterone treatment induced decreased m RNA expression of SOX10,which was well reported to regulate the proliferation,differentiation of OPC and the expression of myelin-related protein in OLGs.These results suggest that HPA axis respond to developmental maternal separation and thus increase corticosterone level,via which the proliferation and differentiation of OPC were inhibited.The OLG loss may dysregulate amygdala function and contribute to the deficit of anxiety-like behavior by maternal separation.