Alterations in expression of mucin, tenascin-c and syndecan-1 in the conjunctiva following retinal surgery and plaque radiotherapy

Abstract.

Purpose: Disturbances of the ocular tear film layer and dry eye symptoms are common complications following retinal surgery and ocular tumour therapy. Examined were the histopathological changes of the conjunctiva following posterior segment surgery and plaque radiotherapy. Methods: Biopsy specimens of the superior bulbar conjunctiva were obtained during cataract surgery between 2 weeks and 7 years following vitrectomy (n=92) or plaque radiotherapy for uveal melanoma (n=20) and from control subjects without previous ocular surgery (n=29). These were examined using conventional histology (HE, PAS, Van Gieson) and immunochemistry [APAAP, using antibodies directed against MUC1, MUC5AC, syndecan-1 and tenascin-C (TN-C)]. The histopathological changes were graded and statistical analysis was performed using Wilcoxon and Kruskal-Wallis rank sum tests. Results: Conjunctival specimens of patients following vitrectomy or plaque radiotherapy for uveal melanoma demonstrated increased epithelial stratification, a significant decrease in the number of PAS- and MUC5AC-positive goblet cells, and distributional changes in expression of MUC1, syndecan-1 and TN-C within conjunctival epithelium or stroma. These alterations – in particular the goblet cell reduction and stromal fibrosis – were most prominent in those patients who had undergone radiotherapy. Conclusions: Posterior segment surgery can lead to morphological alterations of the conjunctiva and distributional changes in ocular mucins, which may cause dry eye symptoms.