Ghrelin expression in the rat’s eye

Purpose The purpose of this study was to evaluate the ghrelin’s ocular tissue distribution in the adult rat’s eye and to confirm previously reported data, describing the identification of ghrelin’s mRNA in the iris posterior epithelium and in the ciliary body non pigmented epithelium. Methods Adult Wistar rats were sacrificed through an intraperitoneal injection of sodium pentobarbital and both eyes were immediately enucleated and processed for cryostat sections and indirect immunofluorescence protocol. Slides were incubated with anti-ghrelin, anti-histone H3 (positive control) and with 2% NGS (negative control) at 4oC for 48 hours and then with secondary antibody containing a fluorescent tag during 1 hour. After incubation slides were examined under a fluorescence microscope. Results We observed immunolocalization of ghrelin in the rat’s ciliary body epithelium. Its major label was in the inner part of that epithelium facing to the stroma of the ciliary processes. This peptide was not localized in the posterior segment, naamely in the retinal pigmented epithelium. Conclusion Ghrelin is locally produced in the eye, mainly in the ciliary processes. Based on these findings, we can conclude that this peptide may play a role as a local regulator of the aqueous humor dynamics and ciliary muscle kinetics.