Comparison of Biomarkers Playing a Role in Pterygium Development in Pterygium and Recurrent Pterygium Tissues

Abstract

Background/Objectives: Pterygium is a nonneoplastic elastotic degeneration characterized by subepithelial growth. It manifests as an ocular lesion originating from the bulbar conjunctiva, extending to the corneal surface, and reaching the visual axis in some cases. Although the exact cause is unknown, prolonged exposure to ultraviolet radiation is considered the most significant contributing factor. Chronic irritation and actinic damage are likely responsible for the typical fibrovascular reactions observed in pterygium. Additionally, growth factors, cytokines, and matrix metalloproteinases play roles in the pathogenesis of pterygium. This study compared recurrent and primary pterygium cases at the molecular level to gain new insights into the etiology of pterygium. Methods: Total protein was extracted from surgical samples of patients with primary and recurrent pterygium, and the levels of transforming growth factor beta 1 (TGF-beta 1), interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6), IL-8, and IL-10 were analyzed using the enzyme-linked immunosorbent assay technique. Target gene expression levels were analyzed using the Delta Delta Ct method after cDNA synthesis from isolated RNA, with normalization to GAPDH and quantification performed with SYBR Green PCR Master Mix. Results: Among the studied cytokines, IL-10 levels were higher in primary pterygium than in recurrent pterygium (722.0 +/- 600.9/421.4 +/- 266.8) (p = 0.0054). Other cytokines (IL-6, IL-8, IL-1 beta, and TGF-beta 1) were detected at similar levels in both primary and recurrent pterygium (p = 0.2986). Additionally, the TGF-beta 1 gene expression was found to be significantly upregulated in recurrent pterygium tissue compared to primary pterygium tissue (p = 0.034). Conclusions: This increase suggests that TGF-beta 1 may contribute to the recurrence mechanisms of pterygium through processes such as fibroblast activation and tissue remodeling. The higher levels of IL-10 in primary pterygium compared to recurrent pterygium indicate an enhanced early protective response aimed at limiting pterygium progression and controlling the inflammatory process.