The Effect And Mechanism Of Icariin On Prenatal Stress Induced Learning And Memory Impairment Of Offspring

Background:Prenatal stress?PS?,as chronic stress,can lead to detrimental effects on offspring,such as depression,cognitive decline,impaired spatial learning and memory,and impaired stress regulation,which will last into adulthood.Icariin?ICA?is one of the main active ingredients of Chinese Medicine Berberidaceae epimedium L,and has many biological activities,such as inhibiting microorganisms,anti-oxidative stress and neuroprotection.Aim:To study the effect and mechanism of ICA on learning and memory impairment of offspring rats exposed to PS,and to provide evidence for the clinical application of ICA and the development of new drugs.Methods:Prenatal restraint stress was used to stress rats during the third trimester of pregnancy,and established the model of learning and memory impairment in the offspring.Female offspring rats were divided into:control group,model group?PS?,low,medium and high dose groups of ICA(20,40,80 mg·kg^-1·d^-1).28 days after intragastric administration,Morris water maze test and eight-arm maze test were used to evaluate the behavioral changes of learning and memory.We used enzyme linked immunosorbent assay?ELISA?,nissl staining,golgi staining,immunohistochemistry and western blotting to investigate the effects and mechanism of ICA on learning and memory impairment in rats exposed to PS.At the same time,glutamate?Glu?induced human neuroblastoma?SH-SY5Y?cells excitatory neurotoxicity cell model was established.Molecular methods such as cell counting kit-8?CCK-8?,immunofluorescence,flow cytometry,and western blotting were used to investigate the effects of ICA on cell viability,apoptosis,mitochondrial membrane potential,intracellular calcium(Ca²⁺)concentration,nitric oxide?NO?levels,and expression of apoptotic pathways and oxidative stress.The improvement effect and mechanism of ICA on Glu induced SH-SY5Y cells excitatory neurotoxicity were analyzed to clarify the neuroprotective effect of ICA.Results:ICA can significantly improve the learning and memory impairment of PS female offspring rats,and significantly reduce the dendritic spines atrophy of pyramidal neurons in hippocampal CA3 region.ICA also significantly reduced the levels of corticotropin releasing hormone?CRH?,corticosterone?CORT?,and adrenocorticotropin?ACTH?in the serum of PS offspring rats,significantly increasing the of neurogranin?Ng?and c-fos protein in hippocampus of offspring rats.In addition,ICA significantly up-regulated extracellular regulated protein kinases?EKR?,calmodulin-dependent protein kinase II?Ca MKII??,and c AMP-response element binding protein?CREB?relative protein phosphorylated expression in the offspring rats.In in vitro cell experiments,ICA significantly increased Glu-induced SH-SY5Y cell viability,inhibited the increase of mitochondrial membrane potential,decreased cell apoptosis,reactive oxygen species?ROS?NO levels,and intracellular Ca²⁺concentration,as well as up-regulation of phosphorylated protein expressions of c-Jun N-terminal kinase?JNK?,mitogen-activated protein kinase P38?MAPK P38?,and active cysteinyl aspartate specific proteinase?caspase-3?.Conclusion:ICA can improve the PS offspring learning and memory decline by reducing hypothalamic-pituitary-adrenal?HPA?axis hyperfunction and up-regulating ERK/Ca MKII?/CREB signaling,and Ng and c-fos protein expression.In addition,ICA also can reduce Glu-induced excitatory neurotoxicity via oxidative stress and apoptosis signaling pathways in SH-SY5Y cells.These showed that ICA may become an effective drug for improving learning and memory.