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

Purpose: Disturbances of the ocular tear film layer and dry eye symptoms ar e common complications following retinal surgery and ocular tumour therapy. Examined were the histopathological changes of the conjunctiva following p osterior segment surgery and plaque radiotherapy. Methods: Biopsy specimens of the superior bulbar conjunctiva were obtained during cataract surgery b etween 2 weeks and 7 years following vitrectomy (n=92) or plaque radiothera py for uveal melanoma (n=20) and from control subjects without previous ocu lar surgery (n=29). These were examined using conventional histology (HE, P AS, Van Gieson) and immunochemistry [APAAP, using antibodies directed again st MUC1, MUC5AC, syndecan-1 and tenascin-C (TN-C)]. The histopathological c hanges were graded and statistical analysis was performed using Wilcoxon an d Kruskal-Wallis rank sum tests. Results: Conjunctival specimens of patient s following vitrectomy or plaque radiotherapy for uveal melanoma demonstrat ed increased epithelial stratification, a significant decrease in the numbe r of PAS- and MUC5AC-positive goblet cells, and distributional changes in e xpression of MUC1, syndecan-1 and TN-C within conjunctival epithelium or st roma. These alterations-in particular the goblet cell reduction and stromal fibrosis-were most prominent in those patients who had undergone radiother apy. Conclusions: Posterior segment surgery can lead to morphological alter ations of the conjunctiva and distributional changes in ocular mucins, whic h may cause dry eye symptoms.