Expression Of Melatonin Receptor 1A In The Cerebral Cortex Of Mice And Its Correlation With Aging

ObjectiveTo determine the distribution of melatonin receptor 1A(Mtnr1a)in the cerebral cortex of mice at different ages,identify the types of nerve cells that express Mtnr1 a,study the relationship between Mtnr1 a and aging,and provide theoretical support for further exploring the function of Mtnr1 a and its impact on aging.MethodsThe distribution of Mtnr1 a in the cerebral cortex of young mice(3 months old)was observed by immunohistochemical staining under a bright field microscope.Natural aging mice of different ages(3,12 and 22 months)were used to detect the protein level of Mtnr1 a in the cerebral cortex of mice of different age groups by western blotting technology,and the expression difference of Mtnr1 a in the cerebral cortex of mice of different months was determined.Multi-immunofluorescence staining was used to identify the cell types expressing Mtnr1 a in the cerebral cortex of adult mice(3 months of age)under confocal laser scanning microscopy.Newborn mice were harvested and cultured in organotype brain sections.D-galactose was used to induce the aging model in vitro.Mtnr1 a c DNA or Si RNA was transfected to regulate its expression.The levels of age-related proteins P53 and Sirt1,autophagy related protein Beclin-1,neural stem cell marker protein Nestin and p-m TOR were detected.At the same time,Mtnr1 a antagonist and Mtnr1 a agonist were used to verify the results of regulation of Mtnr1 a expression level.ResultsMMtnr1a was expressed in several regions of the mouse cerebral cortex.Mtnr1 a was expressed in the cerebral cortex of mice at different ages,and the expression level of Mtnr1 a in the cerebral cortex of mice at 3 months was significantly higher than that at 22 months.Mtnr1 a has obvious co-localization with Neurofilament-heavy(NFH),Nestin and Doublecortin(DCX)in the cerebral cortex of mice.And glial fibers acidic protein(Glialfibrillaryacidicprotein,GFAP)combined with calcium ions adaptor molecule 1(Ionized Calcium-Binding Adapter Molecule1 Iba1)no positioning.Compared with the D-galactose induced in vitro senescence model group,Mtnr1 a protein overexpression increased the expression levels of Sirt1,Beclin-1,Nestin and p-m TOR,but decreased the expression levels of P53 protein.Low expression of Mtnr1 a protein decreased the expression of Sirt1,Beclin-1,Nestin and p-m TOR protein,but increased the expression of P53.The above in vitro results suggest that upregulation of Mtnr1 a overexpression can inhibit cell senescence,while downregulation of Mtnr1 a expression can accelerate cell senescence.Conclusions1.Mtnr1 a is widely expressed in the cerebral cortex of mice.2.Mtnr1 a was expressed in the cerebral cortex of mice of different ages,and the expression level was negatively correlated with age.3.Mtnr1 a is expressed in mature neurons,immature neurons and neural stem cells,but not in astrocytes and microglia cells.4.Upregulation of Mtnr1 a expression can inhibit cell senescence,while downregulation of Mtnr1 a expression can accelerate cell senescence.5.Mtnr1 a may mediate the m TOR pathway and delay senescence by promoting autophagy and inducing neural stem cell renewal and proliferation.