Effect of adenosine on GLAST expression in the retina of a chronic ocular hypertension rat model.

This study was performed to evaluate the effect of adenosine and an adenosine receptor antagonist on the expression of the L-glutamate/L-aspartate transporter (GLAST) in the retina of a chronic ocular hypertension (COH) rat model. COH models were established via the cauterization of three episcleral veins. Measurements of the intraocular pressure of the right eye (COH eye) were taken weekly by a handheld digital tonometer. A total of 10 µM adenosine or 10 µM adenosine + 100 nM SCH442416 solution (2 µl) was injected into the rat vitreous space. The reverse transcription-quantitative polymerase chain reaction, western blotting and immunohistochemistry were used to detect GLAST expression. Compared with the COH group, GLAST mRNA expression was decreased by 33.6% in the group treated with adenosine (n=6, P=0.020) and was increased by 159.6% in the group treated with SCH442416 (n=6, P=0.001). Administration of adenosine decreased GLAST protein expression by 34.7% (n=6, P<0.001), while treatment with the adenosine A2A receptor antagonist SCH442416 increased GLAST protein expression by 48.3% compared with the control COH group (n=6, P<0.001). Immunohistochemical experiments showed that administration of adenosine decreased GLAST protein expression, as compared with expression in the control COH rat retina. Administration of SCH442416 markedly increased GLAST protein expression. The results of the present study may provide a novel method for retinal neuron protection.