Aims To investigate reactive changes of Müller glial cells and astrocytes in rat retinae subjected to hypoxia as well as hypoxia followed by hyperoxia treatments.
Methods A total of 9 adult rats were used in this study. Three rats were used for normal study. The others were exposed to 9% O₂ for 2h._. Of these, 3 rats were killed at 24h following exposure; the remaining 3 rats were immediately exposed to 80% O₂ for 2h, and then killed 24h later. Double immunofluorescence labeling was carried out between nestin and glutamine synthetase (GS), and between glial fibrillary acidic protein (GFAP) and GS antisera in normal and pathological retinae.
Results Enhanced nestin expression was observed in many reactive astrocytes following hypoxia treatment as revealed by whole mount preparation. A novel finding was the induced nestin expression in Müller glial cells and, remarkably, the nestin immunostaining was downregulated to levels comparable to that of the normal rats with immediate hyperoxia treatment. Induced nestin expression by hypoxia colabeled with GFAP in astrocytes, however, remained unaffected after hyperoxia treatment.
Conclusion The induced expression of nestin in both reactive astrocytes and Müller glial cells in hypoxia and differential downregulation between the two glial types after hyperoxia treatment suggest a structural plasticity of the cytoskeletal framework of these cells. The differential response as manifested by the nestin expression after hyperoxia treatment may be related to the functional states of the cells.