FP Localization and Expression in Ocular Tissue

Abstract

Purpose: : The mechanism of the IOP lowering effect of prostaglandin F2alpha analogues is thought to mediate the synthesis of matrix metalloproteinases by mainly acting on FP and decreasing uveoscleral outflow resistance. However, the mode of action has not been well defined. The purpose of this present study was to examine FP localization in the ocular tissue of FP knockout mouse carrying the beta-galactosidase gene at the FP loci and FP mRNA expression in subconjunctival and scleral fibroblast cells.

Methods: : The localization of FP was investigated with the use of eyeballs of wild-type mice and FP knockout mice carrying the beta-galactosidase gene at the FP loci. Enucleated eyes were frozen and 6-micron cryosectioned specimen was obtained. The section was then stained with X-gal. Human subconjunctival fibroblast cells were cultured from resected conjunctiva during conjunctivochalasis surgery with the patient’s consent. Human scleral fibroblast cells were cultivated using imported eyebank eyes. FP mRNA expression was examined by reverse transcription polymerase chain reaction (RT-PCR) from those fibroblast cells.

Results: : FP was localized at the sclera and subconjunctival tissue in the mice. High staining was observed at the sclera adjacent to the ciliary body. The tarsal muscle was well-stained at the eyelid part. There was no expression in the corneal- or conjunctival epithelium. FP-specific mRNA was detected in both subconjunctival fibroblast cells and scleral fibroblast cells by RT-PCR.

Conclusions: : The findings of this study show that FP is expressed at the sclera close to the ciliary body. This result raises the possibility that prostaglandin F2alpha analogues may affect the scleral structure.

Keywords: receptors: pharmacology/physiology • transgenics/knock-outs