Effect of the control proliferation of astrocyte on the formation of glialscars by antisense GFAP retrovirus

Astrocytes play an important role in the formation of glial scars. In order to investigate the effect of inhibiting GFAP gene expression on normal, re active astrocytes and on glial scar formation, the efficiency of the recomb inant antisense GFAP retrovirus (PLBskG) on the growth, cell cycle, morphol ogy and GFAP gene expression of astrocytes in vitro and on the formation of glial scars in vivo has been studied by cell growth curves, flow cytometry , immunocytochemistry, in situ hybridization, RT-PCR and Southern blot. The results confirm the recombinant retrovirus (PLBskG) produced growth suppre ssion and G1 arrest of the normal and injured astrocytes. The infected cell s become round or ellipoid. The cell processes become fine or retracted. Th e intensity of staining of GFAP is reduced. Expression of GFAP mRNA is down regulated. However, in the control experiment, no obvious effects on the m orphology or synthesis of GFAP on cultured normal and scratched astrocytes infected by primary retrovirus vector (PLXSN) have been observed. The super natant of PLBskG has been injected into an injured site by microinjection i n vivo. The number and process lengths of GFAP positive cells are obviously reduced around the injured site. The formation of the glial scar is inhibi ted, showing that the recombinant antisense GFAP retrovirus can effectively inhibit the growth and GFAP expression of normal and injured astrocytes in vitro and the formation of glial scar in vivo. It is suggested that GFAP p lays an important role in glial scar formation.