Abstract
Purpose: :
Conjunctivochalasis (CCh) is an age-related inflammatory ocular surface disease manifesting loose conjunctival folds. The pathogenic role of putative anti-inflammatory TSG-6 in controlling MMP-1 and MMP-3 implicated in CCh remains undefined
Methods: :
Immunostaining of TSG-6 was compared between normal and CCh conjunctiva and Tenon. Second cultures of normal and CCh fibroblasts were transfected with or without TSG-6 siRNA followed by with or without addition of TNF-α or IL-1β. Cell lysates were collected to assess apoptosis measured by the Cell Death Detection ELISA and expression of TSG-6, MMP-1 and MMP-3 transcripts and proteins by qRT-PCR and Western blot, respectively
Results: :
Expression of TSG-6 was constitutive in the in vivo normal conjunctival epithelium and normal conjunctival fibroblasts in vitro. More positive staining of TSG-6 was noted in CCh subconjunctival tissue and Tenon. Expression of TSG-6 transcript and protein was markedly upregulated by TNF-α or IL-1β in normal and CCh fibroblasts. Resting CCh fibroblasts expressed more MMP-1 and MMP-3 transcripts as well as actMMP1 and actMMP3 proteins than resting normal fibroblasts. TSG-6 siRNA upregulated more MMP-1 transcript than MMP-3 transcript in resting normal and CCh fibroblasts, and synergistically with IL-1β upregulated actMMP-1 only in CCh fibroblasts. Cell apoptosis was higher in CCh fibroblasts and further aggravated by TSG-6 siRNA knockdown.
Conclusions: :
TSG-6 exerts an anti-inflammatory function by counteracting transcription of MMP-1 and MMP-3 and by halting activation of MMP-1 in CCh conjunctiva and Tenon Capsule. Further exploration of the causative linkage between TSG-6 and MMP expression and activation might shed light on pathogenesis of CCh.
Keywords: conjunctiva • inflammation