The Morphologic Observation Of Human Embryo Neural Stem Cells

Neural stem call is one kind of neural precursor cells that can self renewal and be introduced to differentiate into the three major CNS cell types: neurons, astrocytes and oligodendrocytes. Tradition viewpoint believed that the neurons and astrocytes are polarized and matured cells. Since Reynolds found the neural stem cell in adult mammalian in 1992, more and more studies in this field have been reported. Neural stem cell study will benefit both academy and the therapy of nerve system disease. Thought neural stem cells in embryonic brain were confirmed, and also, some studies on growth pattern, conditions of culture in vitro, morphology, and differentiation have been reported. Nither the existence of the neural stem cells in the human embryo brain nor the growth rules of the neural stem cells have been illustrated.Commonly, neural stem cells, neurons and astrocytes are exited in proportion in CNS. Nestin is a special antigen of nerve epidermal cell, IV interspace thread, This protein begins to express in nerve epidermal cells. And quantity of nestin starts declining when nerve cells stop migration, and the expression of nestin stop when never cells accomplished polarized. The nestin has been widely used to identify neural stem cell.This experiment collects embryos of volunteer women who were in fetched out and contributed in metaphase pregnancy. The grouping of 13W 17W 21W 25W 29W 33W 37W, each group has not less than 5 embryo samples. Samples were taken from hippOcampus, striatum and ependymal, 3~5 tissue pieces each site. The thickness of the pieces was about 0.5-1 cm. All these samples were riveted with Bouin liquid, and then olefin slices weremade routinely. The tissue slices were stained with Nissl, HE and immunocytochemistric technique. The quantities and the morphologic characters of brain cells and stem cells were studied, of which the purpose is to demonstrate the existence of the neural stem cells in the embryonic human brain, and the possible law or brain develop.Results, nestin positive cells were found in the hippocampus, striatum and under ependymal of the embryonic human brain we observed, of which gestation weeks were 16W 17W 20+3W 22 W 23W 24+5W 25W 27W . All nestin positive cells were displayed in two special morphologic character. One showed a elliptic, rather big cell with diameter of 21+3.4um(n=30), loose karyotin, one or multi-nucleolus, average cytoplast capacity. The other showed rather small round cells with diameter of 18+ 1.8um(n=30),compact karyotin, one or two nucleolus, little cytoplast capacity. Some nestin positive cells grow together to firm a cluster, tightly contact with no obvious cleft between.In this experiment, it is the first time to demonstrate that the embryonic human brain also exist neural stem cells. They were exited by two special characters, one is neural stem cell on the cards, and the other is neural progenitor on the cards. As there were not enough samples, quantity morphology of nestin positive cells in different gestation week embryos and in different district of the human brain cannot be demonstrated. Also, the possible law of develop of neural stem cell need to be further studied.