Abstract
Purpose::
Earlier studies have shown a decreased level of cGMP in vitreous fluid of patients with retinal detachment. The mechanisms causing this decrease and the biological significance are unknown and were therefore the subject of the current study.
Methods::
Experimental retinal detachments were created in pig eyes and vitreous and retinas were analyzed for cGMP expression. After enucleation, the retinas were incubated in the presence of a non-selective phosphodiesterase inhibitor, and the particulate guanylyl cyclase stimulator atrial natriuretic peptide (ANP) or the soluble guanylyl cyclase stimulator sodium nitroprusside (SNP). CGMP was visualized in retinal wholemounts by immunochemistry. CGMP levels in vitreous were determined by ELISA. CGMP was also measured in vitreous of patients suffering from rhegmatogenous retinal detachment to compare cGMP concentrations between pigs and humans.
Results::
The mean vitreous cGMP level in pig eyes after retinal detachment (1.45 pmol/ml) was significantly lower compared to the mean level of cGMP in healthy pig eyes (4.61 pmol/ml)(P = 0.028). No difference in vitreous cGMP level was found between human (1.10 pmol/ml) and pig eyes with retinal detachment (P = 0.30). In the inner retina, both ANP and SNP induced cGMP immunoreactivity in the detached and healthy retina. After incubation with ANP, cGMP could also be detected in the outer nuclear layer of the detached retina, whereas this was not the case in the normal retina.
Conclusions::
The presence of cGMP in vitreous and its decrease after retinal detachment may indicate a potential regulatory role in the physiologic responses of the retina after detachment.
Keywords: retinal detachment • vitreous • retina: neurochemistry