PURPOSES:To investigate the time of neuronie apoptosis in the retinas of Imman fetuses,and its relations with neuronie proliferation and differentiation, METHODS:The retinas of 27 human fetuses from 8th to 38th week of R,~til- ization age and 3 adults were studied by TdT-mediated dUTP nick end labelling(TUNEL) method. RESULTS:Tbe nuctei of labeled apoptotic cells were charaeterised by nuclear marginization,ehromatln condensation and cleseent shape,and some apoptotie bodies were visible in the specimens. The apoptosis of neuroepithelium of fetal rclina took place during 8th to 18th week, Apoptosis of ganglion cells were observed from 1256 to 18th week. The apoptos[s of pholorec, plors were formd from 14th to 2Ist week ,while thai of bipolar neurones and M~ller cells were found from ldth to 28th week. No apoptosb of ocstones were observed in the retinas after 28th week of fertilization age and within the retinas of adults. CONCLUSION:The proliferating cells of neuroepithelium and Ihe neurones which just differetiated from fetal retina might partly undergo apoptosis. The time of apoptosls of differentiated neurones was consistent with the time of the synapses formation between neurones and their targel cells. （Chin J Ocul Fundus Dis,1997,13:67 -69 ）
PURPOSE:To observe tbe development of structure of the retinal blood vessels in human fetuses. METHODS:The retinas of 134 human fetuses from 12-weeks of fertilization to full term and of 4 adults were collected,and examined with immunohlstoebemical method. RESULTS:The examinations showed:(1)The spindle ceils only existed in the retinas of fetuseslt;27 weeks. Till full term,the vessels in ganglion cell layer(GCL)was still budding. (2)BM of all arterioles,venules and capillaries within the retinas of all fetuses and adults,was immunostained after exposure to antlsera against fibronectin.The laminin(LN)and type Ⅳ collagen(COL-Ⅳ)immunoreactive product appeared outside tbe endothelial cells of blood vessels in GCL at 25 weeks and 29 weeks,and tile b LN and COL-Ⅳ immunostaining around four layers of the retinal vessels in tile shape of sbeath appeared at 29 weeks and 32 weeks respectively. (3)As soon as the cords of the endothelial cells were canaized,the smooth muscle cells and perieytes appeared outside the walls. (4)While four layers of the retinal vasculature was spreading to the ora serrata,the glial limitans was formed outside the endothelial cells by the processes of astrocytes and Muuml;ller cells. CONCLUSIONS:Comparing with the adults,certain de fleieneies of the structure of the retinal vessels exisl in the human fetus,and tile endnthelial cells in the retina of the full lerm fetus arc still in proliferation and migration. （Chin J Ocul Fundus Dis,1997,13:153-156）