Pterygial body epithelium domination of pterygial proliferation with TCF4 as a potential key factor.

Aim: To characterize the proliferative capacity of pterygial epithelium in different regions (head, neck and body) of pterygium and explore the function of transcription factor 4 (TCF4) in pterygium proliferation.

Methods: Thirty pterygium tissues and 10 normal conjunctival tissues were obtained from Zhongshan Ophthalmic Center (ZOC) and Guangdong Eye Bank, respectively. Proliferative capacity of head, neck and body in pterygial epithelium was measured using clonal analysis, fold growth analysis and expression profile of proliferative markers revealed by immunofluorescent staining and real-time PCR. The expression of TCF4 was highlighted by double immunofluorescent staining with other proliferation related markers such as proliferating cell nuclear antigen (PCNA) and ATP-binding cassette sub-family G member 2 (ABCG2).

Results: The proliferative potential of pterygial epithelium was higher than that of normal conjunctival epithelium. High expression levels of proliferative markers (P63α, PCNA and ABCG2) in pterygial body epithelium were observed in immunofluorescent staining and real-time PCR (<0.05). Also, epithelial cells isolated from pterygial body demonstrated higher proliferative capacity in clonal analysis and fold growth analysis, than those isolated from the head and neck regions. The TCF4 expression in pterygial epithelium was similar to other proliferative markers (P63α, PCNA and ABCG2), as higher in pterygial body than head and neck. Moreover, TCF4 showed coexpression with other proliferation-related markers (PCNA and ABCG2) in the double immunofluorescent staining experiment.

Conclusion: The proliferative capacity in pterygial body epithelium is prominent than the head and neck regions, and upregulated TCF4 may be associated with enhanced proliferation in the pterygium.