Abstract
Abstract: :
Purpose: To examine the effect of rapamycin on the corneal neovascularization and its related stimulating factors (in vivo) and on the proliferation and the migration of human umbilical vein endothelial cells (HUVEC) (in vitro). Methods: Corneal wound was induced with 1N NaOH for 5 seconds in adult BALB/C mice. Rapamycin (0.5 mg/kg) was given intraperitoneally once a day for 12 days. The area of corneal neovascularization was quantified by a photodocumentation. Gene expression related with angiogenesis, substance P, HIF–1α, IL–1ß, TNF–α, VEGF, VEGFR–1 and PlGF, was measured in the corneal tissue and the peripheral blood by RT–PCR and ELISA at 1, 3, 5, 7, 10 and 14 days following alkali wound (in vivo). After the treatment of rapamycin (0∼1000 ng/ml), HUVEC cell migration and proliferation were analyzed by a double–chamber method and MTT assay, respectively (in vitro). Results: The corneal neovascularization was significantly reduced in the animals treated with rapamycin when compared to control (p <0.05). Gene expression of substance P, PlGF, HIF–1α and IL–1 was inhibited by rapamycin at earlier period (1 to 3 days), with VEGFR–1 gene expression being suppressed for first 7 days. The protein level of substance P and VEGF was significantly decreased in animals treated with rapamycin, the former earlier and the latter later, respectively (p<0.01) (in vivo). The migration and the cell growth of HUVEC were strongly inhibited by rapamycin in the dose–dependent manner (p<0.05) (in vitro). Conclusions: The rapamycin may inhibit the corneal neovascularization by the suppression of various factors (substance P, HIF–1α and VEGF) in mice. In addition, this effect can be explained in part by the inhibition of the migration and proliferation of vascular endothelial cells. Therefore, rapamycin may be a useful agent for the treatment of corneal diseases with neovascularization.
Keywords: cornea: endothelium • neovascularization • vascular cells