Study On Structure And Adult Neurogenesis Of Goat Hippocampus

The structure and cell types of the hippocampus in adult goat were observed by the traditional staining of HE, using Double-cortin(DCX) as a specific marker of the newborn neurons which located in SGZ of dentate gyrus in goat hippocampus, the goat hippocampal radial glial cells, astrocytes and microglia and the distribution of some receptors and calcium-binding protein were observed with the GFAP/NeuN double immunofluorescence labeling method, EB3/DAPI, Calretinin/DAPI, ErbB4/DAPI, Iba1/DAPI, bNOS/DAPI fluorescent double labeling method. The results were as follows:1. The goat hippcampus mainly contains dentate gyrus, hippocampus proper, and both of them stratify clearly. The hippocampus proper can be divided into alveus, stratum oriens, stratum pyramidale, stratum radiatum, stratum lacunosum moleculare.The dentate gyrus can be divided into three layers: the molecular layer, granul cell layer and hilus.The goat dentate gyrus showed regular C shaped. Granule cells, mossy cells and pyramidal cells are the three major cell types of the hippocampus formation.The pyramidal cells arranged densely and orderly, the somata are larger than those of granul cells.The pyramidal cells send a large apical dendrite towards the molecular layer.The pyramidal cells in CA1 region are obviously divided into two layers,while the pyramidal cells in CA3 region form a close uniform layer.2. The results of DCX labeling showed that goat hippocampus existed adult neurogenesis. The somata of most DCX- positive cells, which were distributed individually or together, mainly located in the deepest part of the granule cell layer closing to hilus observed with DCX/DAPI fluorescent double labeling method. The branched DCX-positive dendrites extended from somas towards into molecular layer.3. A large number of GFAP-positive cells located in deepest part of the granule cell layer closing to hilus, and their cytoplasm and single processes were GFAP-positive, while the nuclei were negative. NeuN-positive neurons in dentate gyrus formed a densely packed granule cell layer.4. A large number of Iba1-positive cells were scattered in the whole hippocampus, and specially, the density of Iba1-positive cells in granular cell layer, hilus and stratum lacunosum moleculare are much higher than those in other parts of hippocampus.5. ErbB4-positive cells, bNOS-positive cells, calretinin-positive cells, EB3-positive cells could be found in the whole hippocampus. The density of these four kinds of positive cells in granule cell layer and hilus were much higher than those in other parts.The ratios from high to low of four type cells in hilus were as follow: EB3﹥Calretinin﹥bNOS﹥ErbB4.