The Study On The Differentiation Of O-2A Progenitor Cells And Expression Of The Differential Antigens Of Type 1 And Type 2 Astrocytes

The central nervous system ( CNS ) is characterized by an immense structural complexity with intimate association of its constituent cell types: neurons and different types of glial cells. As a major glial cell subtype, astrocytes take on most important status in number and distribution, either in morphology and function. According to recent studies, astrocytes not only nourish and protect neurons, but take part in both other function and senior activites of CNS.According to the theory of astrocyte lineages including T1A lineage and O-2A lineage, astrocytes contain two populations: type-1 astrocytes ( T1A ) and type-2 astrocytes ( T2A ). The former population is derived from T1A progenitor cells that express Ran-2 epitope, whereas the later population and oligodendrocytes ( OL ) derived from bipotential O-2A progenitor cells that express A2B5 epitope.Objective The present study includes: (1) to establish the method of obtaining more pure O-2A progenitor cells. (2) to further understand the bipotential differentiation of O-2A progenitor cells in vitro and . (3) to study the differential expression of cytoskeletal protein ( vimentin ) and calcium-binding protein ( S-100 ) between the development of T1A and T2A. so as to bulid a solid foundation for the subsequent research.Methods (1) Based on the differential properties of cellular adhesions and developmental time-course, O-2A progenitor cells were isolated at the onset of the layer of T1A with a standard shaking method and then purified with the differential adhesion method combining with using the growth factors, and further detected their viabilitieswith the method of MTT. (2) With cell culture in vitro, O-2A progenitor cells differentiated into type-2 astrocytes or oligodendrocytes depending on the culture medium. (3) With immunocytochemical label, the expression of vimentin and S-100 3 in T1 A and T2A were observed.Results (1) The purified O-2A progenitor cells presented typical morphology which were bioploar or tripolar. Identified by immunocytochemical, the O-2A progenitor cells were A2B5-positive and the purity of them was 95%. (2) O-2A progenitor cells developed in vitro into T2A when cultured in fetal calf serum-containing medium, whereas they developed into OL when cultured in serum-free medium. (3) T1A and O-2A progenitor cells expressed both vimentin and S-100β . The immature T2A only expressed S-100β , whereas the mature T2A did not express the antigens.Conclusion (1) A method that acquiring enough O-2A lineage cells have been established. (2) O-2A progenitor cells possess the characteristics of bipotential differentiation and they can be induced to differentiate into T2A or OL when cultured in different medium. (3) Tl A and T2A are different in morphology and antigenic expression of differentiation. (4) The expression of the cytoskeletal protein and calcium-binding protein may exhibit difference of time and cell lineage during the development of astrocytes.