Comparative Analysis About Adult Neurogenesis And Hippocampal Structure Characteristic Between Pig And Mouse

The hippocampus is an important structure in brain,it not only plays an important role inlearning,memory and cognition process,but also control the animal appetite and foragingbehaviors.Hippocampal damage can lead to some nervous system diseases. Through adultneurogenesis hippocampus everfount to generate new neurons,these new neurons joining inthe existed neural network to make these functions proceed smoothly.So the normal operationof hippocampal function and adult neurogenesis are inseparable. The pig as an importantlivestock animal, if we are able to control their appetite and eating,it will reduce the feedingdifficulties.But to achieve this point, the pig hippocampal structures should be fullyunderstood.And also the function of hippocampal should be made a thorough research,thiswill contribute to the control of nervous system diseases.But so far,adult neurogenesisresearch mainly focused on small kind of animals.Research about pig adult neurogenesishas not been reported.Previously,adult neurogenesis research were mainly carrried on bylabeling proliferating cells technology,but this technique is not suitable for large animalneurogenesis research.In recent years, doublecortin as a new kind of immature neuronalmarkers was widely used in adult neurogenesis research. In this experiment, the structure andneurogenesis characteristics of the adult pig and mouse hippocampus are compared andanalyzed.The main research results are as follows:1. BrdU/DCX fluorescence double labeling results proved that DCX labeling method canlabele newborn neurons, and the proliferation of newborn neurons can directly reflect thesituation of adult neurogenesis, therefore, DCX markers can be used to study adultneurogenesis.2. The results of DCX labeling showed pig and mouse hippocampus both existed adultneurogenesis,which located in subgranular zone.From birth to maturity,these newbornneurons experienced a process of dynamic change.Cell body can move in the granule celllayer, and their dendrites and axons extended in opposite directions.Their dendrites emited alarge branches in the molecular layer,terminating at the hippocampal fissure.Axons wentthrough the hilus senting branches, and finally they assembled into a beam at the junction ofpyramidal layer and hilus.Then it extended along the pyramidal layer,terminating at in a CA3 area and CA2area.3. Pig and mouse hippocampal adult neurogenesis has some obvious differences.Mouseneonatal neurons are relatively poor,their dendrites and axons are clearly visible.For pig,itsdendrites spread almost all over the whole of the molecular layer.From data analysis, we cansee newborn neurons’ average soma area of adult pig hippocampus was smaller thanmouse.But its average relative dendritic length was longer,as well as the number of newbornneurons in the dentate gyrus unit length were greater than mouse.4. Pig hippocampal structure also can be divided into dentate gyrus, and subiculum.Thehippocampal part can be divided into Pig hippocampal structure also can be divided intodentate gyrus, and subiculum.The hippocampal part can be divided into alveus,stratumoriens,stratum pyramidale,stratum radiatum,stratum lacunosum moleculare.The pyramidalcell arranged densely and orderly,the cell body is large and conical.The pyramidal cell sendsa large apical dendritic protrusions towards the molecular layer.Hippocampal dentate gyruscan be divided into three layers: the molecular layer, granular cell layer and polymorphic celllayer.The pig hippocampal cell component,layered and basic structure were almost the sameas mouse,but the pig hippocampal dentate gyrus showed irregular C shaped.To sum up, there was a continuous production of new neurons in both pig and mousehippocampal subgranular zone.Compared to mice, these new neurons of pig were more dense,having more dense dendrites and branches, these reflect the adult neurogenesis level of pigwas higher than that of mice,these also meaned the pig had a more developed and complexbrain than mouse.The same as the mouse, the pig hippocampus is composed of two parts, theregional layers were basically the same. But each layer of the two animals have differentcharacteristics, shape and the inner cell distribution.