Increased Expression of Aquaporin-1 and Aquaporin-3 in Pterygium

Abstract

Recent studies have shown that aquaporins (AQPs) play an important role in proliferating tumor microvessels and angiogenesis. In this study, the authors investigated the expression of aquaporin-1 (AQP1) and aquaporin-3 (AQP3) in pterygial and normal conjunctival tissues. Fifteen patients with pterygium were enrolled in the study. Pterygium was excised, and a conjunctival rotational flap or autograft was inserted. Normal conjunctival tissue was obtained from the flap or graft. Western blot analysis was performed to assess the expression of AQP1 and AQP3 in pterygial and normal conjunctival tissues. Tissue localization of AQP1 and AQP3 was determined by immunohistochemical analysis. AQP1 and AQP3 are localized in the epithelial and subepithelial regions in pterygial and normal conjunctival tissues. Protein expression of both AQP1 and AQP3 was elevated in pterygia when compared with conjunctival tissues. The significant increase in protein expression of AQP1 was 3-fold in pterygium over normal conjunctiva (P = 0.004) and 2-fold increase in AQP3 expression of pterygium was detected (P = 0.02) according to densitometric analysis. Elevated protein expression of AQP1 and AQP3 was observed in pterygial tissues when compared with normal conjunctiva. The data suggest that the increased expression of AQP1 and AQP3 in pterygial tissues may be involved in the pathogenesis of pterygia, and therefore, AQP1 and AQP3 are potential therapeutic targets for preventing or delaying the progression of the disease.