Abstract
Purpose :
Pterygium is a wing shaped fibrovascular growth on the ocular surface. Epidemiologic studies have linked pterygium formation to various chronic inflammatory conditions, including ultraviolet radiation (UV) exposure. We identified the gene expression profiles in pterygium using gene microarray analysis and examined the expressions of pterygium-related genes in UV-B induced human primary corneal epithelial cells (HCEpC) and conjunctival fibroblast cells (HConF).
Methods :
Apical portions of pterygium and control conjunctiva tissues were evaluated for comprehensive gene expression levels using a gene-chip microarray. In addition, primary HCEpC and HConF were exposed to UV-B. Expressions of a panel of potential target genes were evaluated by real time-PCR. Data were reported as means ± SDs and analyzed by 1-way ANOVA, followed by a t test when appropriate, with p< 0.05 deemed significant.
Results :
The expression of genes related to extracellular matrix, extracellular regions, extracellular matrix organization and vasculature development were upregulated in pterygium tissues. The expression of 10 genes was significantly modulated (>X10) in these tissues and Keratin 24 (KRT24) and matrix metalloproteinase 9 (MMP-9) were 49.446 and 24.214 times upregulated. UV-B exposure (50 and 100 mJ/cm2) induced the upregulation of the expressions of MMP-9 in HCEpC (Fig. 1A: *p<0.03; **p<0.002) and HConF (*p<0.0007; *p<0.006; ***p<0.02) (Fig. 1). Exposure of 100 and 200 mJ/m2 of UV-B to HCEpC induced the expressions of KRT24 mRNA with significance in HCEpC (p<0.05). Expression of KRT24 mRNA was not detected in HConF. We found that KRT24 is specifically expressed in HCEpC.
Conclusions :
These results provide evidence that progression of pterygium involves the modulation of extracellular matrix related genes and vasculature development and the up-regulation of KRT24 and MMP-9 by UV stress. UV radiation may promote the modulation of these pterygium related genes and induce the initiation and progression of human pterygium.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.