UP-REGULATION OF GLIAL FIBRILLARY ACIDIC PROTEIN IN THE RETINA OF PRIMATE EYES WITH EXPERIMENTAL GLAUCOMA

Objective: To identify molecular mechanisms of retinal responses to in traocular pressure elevation in primate experimental glaucoma. Methods : An experimental glaucoma model was created by repeated laser trabecu lophotocoagulation. After the preparation of complementary DNAs from e xtracted total RNAs in the retinas, polymerase chain reaction (PCR) ex periments were performed for the following screening target genes: bet a-tubulin beta(2) and beta(5) and glial fibrillary acidic protein (GFA P). To investigate the amplified sequences derived from the PCR experi ments, sequencing, subcloning, and Southern blot analysis of PCR produ cts were performed. In addition, an immunohistochemical analysis was p erformed in an attempt to show the distribution of the target gene pro ducts in the retinas. Results: A series of PCR experiments suggested u pregulation of gene expression for GFAP but not for beta-tubulins. Seq uencing of the PCR products and results of the Southern blot analysis showed that the amplified sequences were derived mainly from the targe t gene, GFAP, and that increased expression of GFAP was found despite the severity of glaucoma. Immunohistochemical studies also demonstrate d increased expression of GFAP proteins in Muller cells and astrocytes in the retinas of primate eyes with experimental glaucoma. Conclusion : Our study showed up-regulation of GFAP at gene and protein levels, w hich suggests that glial components in the retina may contribute to th e pathologic processes induced by elevated intraocular pressure.