The Effect Of Thymosin Beta4on Corneal Neovascularization In Rabbit

The normal cornea is an avascular structure, that is necessary for the corneal transparency and good vision. Corneal neovascularization may play a part in the corneal wound healing, but a chronic corneal neovascularization can result in vascular pannus, and damage of corneal microenvironment and corneal immune privilege. It is significant to find an effective solution for corneal neovascularization. Thymosin beta-4has multiple biological functions such as preventing cell apoptosis, reducing inflammation and healing the corneal wound. Since the research of thymosin beta-4on corneal wound healing is still in an early stage of clinical tests, it is not clear whether the thymosin beta4is a good therapy to corneal neovascularization.The4th generation of rabbit primary culture umbilical vein endothelial cells were respectively incubated in a96-well culture plate, then co-incubated with different concentration of thymosin beta-4(0,10ng/mL,100ng/mL,1000ng/mL), every dose added into12holes. After co-incubation of24hours the growth activity of the4groups of cells were tested by cck-8method with1hour for the optical density difference(OD)value.A rabbit experimental model of the basic Fibroblast Growth Factor-induced corneal neovascularization by a corneal pocket assay was established to evaluate the effect of thymosin beta-4on corneal neovascularization. Twenty-four rabbits were randomly divided into4groups. With different concentrations of thymosin beta-4(0.1μg/μL,1μg/μL,10μg/μL) three were drug groups and the other was control group with PBS. All postoperative treatments were administered2times daily. Photographs were taken on a digital camera or a slit lamp. The area of the corneal neovascularization and the inhibition ratio were calculated by measuring the length of the corneal neovascularization.The experimental results showed that100ng/ml and1000ng/ml of thymosin beta-4significantly promoted the proliferation of the rabbit umbilical vein endothelial cells in vitro.The inhibition ratio of1μg/μL thymosin beta-4was the highest in the three thymosin beta-4drug groups. The inhibition ratio of10μg/μL thymosin beta-4was lower than1μg/μL thymosin beta-4at the early stage, but higher after a few days. Compared with control group, a significant inhibition of corneal neovascularization by the three different concentrations of thymosin beta-4were found (P<0.05). The two groups of1μg/μL thymosin beta-4and10μg/μL thymosin beta-4not only inhibited the growth of corneal neovascularization but also promoted the regression of corneal neovascularization. However, the group of0.1μg/μL thymosin beta-4just inhibited the growth of corneal neovascularization.The experiment results showed a conclusion that thymosin beta-4promoted the proliferation of the rabbit umbilical vein endothelial cells in vitro, but significantly inhibited on corneal neovascularization in vivo.