Changes in Expression of Glutamate Transporters in the Rat Retinal Glial Cells under Various Culture Conditions.

Abstract

Abstract: : Purpose: To investigate the changes in expression of glutamate transporters (GLTs) in the rat retinal glial cells under the various culture conditions, hypoxia or different status of confluence. Methods: Retinal glial cells were isolated from 3–day–old Sprague–Dawley rats as described previously. Reverse transcription polymerase chain reactions (RT–PCRs) ascertained the GLT–mRNAs. Western blotting and immuno–histochemical observation confirmed the GLT–proteins. Real–time PCR investigated the changes in expression of GLT–mRNAs. Retinal glial cells cultured under hypoxic circumstance (5%O₂ or 10%O₂,) or cultured under 20%O₂ were subject to hypoxia–induced changes in expression of GLT–mRNAs, and retinal glial cells under the confluent status or under the propagating status (6 hours after the passage) were subject to confluence–related changes in GLT–mRNAs. Results: mRNAs and proteins of GLAST, GLT–1, and EAAC1 were identified in the cultured rat retinal glial cells. Hypoxic culture condition and difference in confluence did not effect the expression of GLAST–mRNA, while these culture conditions up–regulated the expression of GLT–1–mRNA. Hypoxic culture conditions slightly up–regulated the expression of EAAC1–mRNA, while nonconfluent retinal glial cells markedly up–regulated the expression of EAAC1–mRNA. Conclusions: This is the first report in which expression of EAAC1 was ascertained in the cultured retinal glial cells. Different expressions of GLT–mRNAs under the various culture conditions may be deeply involved in glial cell–related retinal diseases.

Keywords: retinal glia • hypoxia • immunohistochemistry