| Objective: Autism spectrum disorders is a serious neurodevelopmental disorder that occurs in the early stage of infancy.Pregnancy and infancy are two key periods of neurodevelopment of offspring.Their brains are affected by blood brain barrier.The integrity of the blood brain barrier is essential for the normal function of the central nervous system.Harmful substances can cross the blood brain barrier into the brain parenchyma and cause secondary pathophysiological reactions.In daily life,aluminum compounds are mainly exposed to the human body through environmental,dietary,pharmaceutical and occupational pathways,which can increase the permeability of the blood brain barrier and destroy the blood brain barrier.The formation and maintenance of blood brain barrier function are regulated by a variety of signaling pathways,among which Sonic hedgehog and WNT pathways are important signaling pathways that regulate the blood brain barrier,and the two pathways have been shown to interact on multiple levels.Serum Shh protein levels were found to be significantly elevated in children with ASD and correlated with ASD severity.Therefore,in this study,a rat model of autism was established with the help of aluminum to observe the regulatory effects of SHH and WNT pathways on the blood brain barrier,explore the role of SHH and WNT pathways in the process of blood brain barrier injury caused by peripheral inflammation and clarify its mechanism,so as to seek new targets for the prevention and treatment of neurodevelopmental disorders.Methods: 1.The rat model of autism was established with the help of aluminum,and the growth and development of the offspring rats were observed,and the general behavioral and neurobehavioral detection were performed.Three chamber social interaction task were used to evaluate the social interaction ability of pups.Open field test use to evaluate the anxiety behavior of young rats.T maze task and Marble burying task were used to evaluate the repetitive and stereotyped behavior of rats.The levels of IL-1β and TNF-α in serum and brain tissue were determined by ELISA.The expression levels of tight junction protein and SHH pathway protein were detected by western blotting.2.An intervention group was established by intraperitoneal injection of purmorphamine(PUR),and the growth,development and neurobehavioral changes of piglets in each group were observed.The permeability of blood-brain barrier was estimated by Evans blue test,immunofluorescence staining for CLDN5 and western blot.Morphological changes of cerebral cortex were observed by HE staining.The levels of IL-1β and TNF-α in serum and brain tissue were determined by ELISA.The protein expression levels of SHH and WNT pathways were detected by western blot.The expression levels of UNC5B-LRP6 and SMO-β-catenin were detected by immunofluorescence staining.The interaction of UNC5 B with LRP6,SMO and β-catenin was verified by co-immunoprecipitation.Results: 1.Compared with the control group,the model group showed growth retardation,abnormal general behavioral detection,abnormal social behavior deficits,abnormal social novelty preference behavior,increased repetitive and stereotypical behavior and anxious behavior,increased release of inflammatory factors in serum and prefrontal cortex,decreased expression of tight junction protein,decreased expression of SHH,SMO and GLI1 proteins,and destroyed blood brain barrier.The autistic rat model with aluminum assisted LPS showed more obvious autism-like behavior.2.Compared with the control group,the model group showed growth retardation,social behavior defects and abnormal social novelty preference behavior,and increased repetitive stereotyped behavior and anxious behavior.Pathological changes of cerebral cortex showed clear structure of cerebral cortex cells and regular arrangement of neurons in control group.In the model group,the number of nerve cells was reduced,the shape was irregular,and the nucleus was shrunk.The release of inflammatory factors in serum and prefrontal cortex increased in model group;The content of exogenous Evans blue in brain tissue increased,the expression of tight junction protein decreased,and the level of CLDN5 decreased as detected by immunofluorescence staining,leading to the destruction of the blood brain barrier.Compared with the control group,SHH and WNT signaling pathways were inhibited in the model group.Immunofluorescence colocalization and immunoprecipitation showed that UNC5 B interacts with LRP6,SMO and β-catenin.After PUR intervention,all of the above injuries were reduced to varying degrees.Conclusions: Aluminum combined with LPS model can better simulate the core symptoms of autism.The blood brain barrier was damaged in autistic offspring,and prefrontal cortex inflammation increased which may be related to the inhibition of SHH pathway and the down-regulation of WNT pathway.SHH pathway agonist PUR exerts a protective effect against autistic on the blood brain barrier injuries through up-regulating of SHH/UNC5B/β-catenin pathway. |
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