Effects And Mechanisms Of Dopamine On Ethanol-induced Neuronal Apoptosis Of Early Developmental Rat Retina

Background: Prenatal alcohol exposure results in fetal alcohol spectrum disorder(FASD),and the most severe form of fetal alcohol syndrome(FAS)include craniofacial malformation,structural abnormalities of the nervous systems,and long-term neurobehavioral disorders.Previous studies reagard apoptosis of early development neuron as the primary cause of(FASD),while the mechanism that ethanol-induced neruon aopoptosis occurs in nervous system during early development is not clear.During early development,nervous system show synchronized spontaneous network activity.This activity and gene together can regulate neuron growth,differentiation,migration and apoptosis et al.Our preliminary study shows that ketamine block synchronized spontaneous network activity and induce neuruonal aopoptosis in the early developmental rat retina.While the the relationship between synchronized spontaneous network activity and ethanol-induced neuronal apoptosis is unknown.Methods: In this study,We used whole-mount cultures of rat retinas to explore the relationship between synchronized spontaneous network activity and ethanol-induced neuronal apoptosis,and possible protect procedures,combined with the patch clamp electrophysiological recording,immunohistochemistry.Results: We found ethanol inhibited synchronized spontaneous network activity and induced neruonal apoptosis in a dose-dependent manner in postnatal day 7(P7)rat retina;Dopamine enhanced synchronized spontaneous network activity,reduced physiological and ethanol-induced neuronal apoptosis in P7 rat retina.We further explored the association between dopamine D1 and D2 receptors,adenosine A2 A receptor,cAMP/PKA signaling pathway and the protection of dopamine,which all involved in the protection of dopamine on ethanol-induced neuronal apoptosis in P7 rat retina.In addition,using high-throughput sequencing technology,we explored the relationship between the change of circular RNA(circRNA)and physiological neuronal apoptosis in rat retina during early development.The results showed the circRNA species at P7 rat retina(7,201)was higher than that at P3(2,654)and P12(5,628).Further more,15 circRNAs whose host genes are associated with apoptosis were differentially expressed during the early development.Specifically,7 circRNAs(from gene Optn,Thoc1,Rbm5,Ddx19 a,Bnip2,Pias1,Naa35)expressed at P7 rat retina were quite lower than that at P3 and P12;6 circRNAs(from gene Rere,Arhgap10,Birc6,Ranbp9,Epha7,Braf)expressed much higher at P7 rat retina than that at P3 and P12;2 circRNAs upregulated or downregulated gradually during early development in rat retina(fom gene Akt or gene Melk).In addition,age-dependent physiological neuronal apoptosis was confirmed by cleaved caspase-3-positive cell and TUNEL-positive cell ratio,indicating circRNAs may play a role in neuronal apoptosis,providing possible targets for ethanol-induced developmental neuroapoptosis.Conclusions: In summary,Dopamine reduced ethanol-induced neuronal apoptosis in P7 rat retina;circRNAs may play a role in neuronal apoptosis;which provide possible method of prevention and therapies for FASD.