Adenosine receptor protein changes in guinea pigs with form deprivation myopia

Recent results have shown that treatment with the non-selective adenosine antagonist 7-methylxanthine (7-MX) reduces the development of form deprivation myopia (FDM) in guinea pigs. The aims of this study were to identify the presence of adenosine receptors (AdoRs) in the eye wall of the guinea pig and to determine their possible changes during form deprivation.

Three-week-old guinea pigs were monocularly treated with a translucent lens to induce FDM. After 21 days, samples were taken from the posterior eye wall and examined with immunofluorescence confocal microscopy for the presence of AdoRA1, AdoRA2A, AdoRA2B and AdoRA3 proteins. Western blot analysis was used to quantitate AdoRs in samples from the retina, choroids and sclera.

All four subtypes of AdoR were expressed in the posterior wall of the guinea pig eye, although AdoRA3 only weakly. Twenty-one days after the induction of myopia, we observed a significant decrease in protein expression for AdoRA1 (- 25.5%) and an increase in protein expression for AdoRA2B (+ 66.7%) in the retina of FDM eyes.

AdoRs of all subtypes are expressed in the retina, choroids and sclera in guinea pigs and may play a role in the regulation of eye growth. The changed pattern of AdoR expression during form deprivation confirms that pharmaceutical intervention targeting AdoRs may reduce myopia progression.