Abstract
Purpose::
TRX (thioredoxin) and GRX (glutaredoxin) are endogenous antioxidant proteins involved in the maintaining the balance of cellular redox homeostasis. The purpose of this study was to analyze the expression of TRX and GRX genes in normal retinas and in retinas of a rat glaucoma model.
Methods::
A rat glaucoma model was generated with chronic, moderately elevated intraocular pressure (IOP). GRX 1 and 2, as well as TRX 1 and 2 mRNA levels were analyzed by semi-quantitative RT-PCR. In situ hybridizition was carried out with digoxigenin-labeled sense and antisense riboprobes to localize the expression of these genes in the retina.
Results::
In normal retina, expression of GRX1, GRX2, TRX1 and TRX2 redox genes was detected by RT-PCR. In situ hybridization showed expression of GRX1, GRX2, TRX1 in different retinal cell layers, including the ganglion cell layer (GCL). TRX2 mRNA expression was mainly observed in the GCL. Furthermore, approximately 2-fold increased TRX2 mRNA expression was observed with semi-quantitative PCR in glaucomatous retinas compared to control ones two weeks after IOP elevation (n=3). No changes in GRX1, GRX2 and TRX1 mRNAs levels were detected in experimental versus untreated retinas (n=3).
Conclusions::
Predominant expression of TRX2 mRNA in the GCL and its upregulation after IOP elevation suggest its involvement in glaucomatous neurodegenerative processes.
Keywords: apoptosis/cell death • retina • antioxidants