Selection Of Reference Genes And Dementia-Related Pathological Study Of Brain Tissue In Human Brain Bank

BackgroundBrain banks are built for gather,store,and provide human brain tissue for researcher to study Neurodegenerative diseases like Alzheimer' s disease and Parkinson's disease.Brain tissues can be used for detection directly the differential transcription expression of the target gene and find the gene transcription products that can affect these neurodegenerative pathology between diseased and healthy brain.It is necessary to select the appropriate internal gene to normalize the expression of target gene when using RT-qPCR method to study gene transcription expression.However,even the same internal gene may has significant expression difference in same tissue from different samples.So it is essential to find some suitable internal gene that has strong expression stability in different brain samples to normalize the expression of target gene accurately.ObjectiveThe purpose of this study is to identify suitable reference genes for gene expression under different donor anamnesis,age of donors,samples storage time and post-mortem interval(PMI)in brain tissue from 18s,ACTB,CYCl GAPDH,HPRT1,UBC and TBP.MethodsWe assessed transcription level of 7 commonly used reference genes(18s,ACTB,CYCl,GAPDH,HPRT1,UBC and TBP)in prefrontal cortex(PFC)tissue from 163 brain samples and split into four groups according to donor anamnesis,age of donors,samples storage time and PMI,subsequent date analysis be performed by comparative delta-Ct method,geNorm and NormFinder algorithms.ResultsOur results show that the expression level of ACTB?CYC1?GAPDH?HPRT1?UBC and TBP have an inverse correlation with PMI and the age of donors.In addition,CYC1 and TBP have the most stable mRNA expression level in postmortem human PFC tissue from 163 brain samples by geNorm and NormFinder algorithms.ConclusionThe expression level of mRNA in brains may decrease along with the increase of donor' s age and PMI implys the acquisition of brain tissue had better be controlled within the lower PMI in no more than 36h.CYC1 and TBP have lower expression stability compared with GAPDH,ACTB,HPRT1,UBC and 18s,which indicated that CYC1 and TBP have higher expression stability in different brain tissues and be used as suitable internal gene to normalize the expression of target gene for transcription studies when using human brain tissues.BackgroundAlzheimer's disease(AD)is the most common type of neurodegenerative disease that causes dementia in the elderly.Senile plaques,which are extracellular deposits of the ?-amyloid(A ?)peptides,and neurofibrillary degeneration,which is best exemplified by neurofibrillary tangles(NFTs),are considered essential neuropathological hallmarks of AD which lead to neuronal loss eventually.Lewy body dementia(LBD)is the second most common type of degenerative dementia in the elderly.Inclusions,which are deposits of the ?-synuclein(Lewy bodies,and Lewy neurites)proteins,are considered as the neuropathological feature of LBD accompanying neuronal loss.Parkinsonism and olfactory dysfunction always presents at the early stage of the disease and along with progress of the disease,visual hallucinations and cognitive impairment usually occurs.The pathological between AD and LBD may have some connections,and more advanced dementia symptom may occur in patients with LBD combined with AD pathology.ObjectiveThis study aimed to investigate the distribution of AD and LBD related pathology(LRP)lesion in the donors and research the correlations between the postmortem neuropathological change in the brains and the antemortem cognitive performances in the donors.MethodsA total of 127 human brain tissue with antemortem everyday cognition(Ecog)information were performed in AD(A ??Tau and neuritis plaque)and LBD(a-synuclein)diagnostics by immunohistochemistry then analysis the relationship between the postmortem pathological change and the antemortem Ecog information of donors.ResultsIn our study we used immunohistochemistry technique to diagnosis AD and LRP in 127 cases of brain tissue.We find 44 cases of AD,22 cases of LRP,12 cases(54.5%)of LRP combined with AD,and 4 cases(80%)of 5 diffuse neocortical LRP were combined with AD pathological changes.With the aggravation of the pathological progress of AD and LBD,the antemortem Ecog score of donors displays an upward trend,and the cognitive ability of the AD cases combined with diffuse neocortical LB pathology was significantly lower than other AD cases(P<0.01).ConclusionBased on the results of our experiment,half of the LRP cases were combined with AD neuropathological change in the CAMS/PUMC Human Brain Bank.The AD cases combined with diffuse neocortical LB pathology may have more advanced dementia according to their antemortem everyday cognition(Ecog)information.