Human Amniotic Membrane For Conjunctival Squamous Metaplasia And Its Mechanism Of Action Of Experimental Research

PURPOSE: Squamous metaplasia is a common pathologic process that happens in ocuLar surface epithelium. The present study was undertaken to investigate the effects and mechanisms of human amniotic membrane on squamous metaplasia of human conjunctival epithelium in an ex vivo culture model created by culturing conjunctiva tissues at an air-liquid interface .METHODS: Human normal conjunctival tissues were cultured under airlift manner with or without human amniotic membrane (AM) or AM extract(AME) for different durations up to 4 days ,8 days or 12 days. Conjunctival epithelial cell differentiation and proliferation were evaluated by K10, MUC5AC,Pax6, Ki67,K14,K16 and p63 expression. Wnt signaL related proteins such asβ-catenin and phospho-β-catenin were studied by immunostaining.RESULTS: Squamous metaplasia was induced in conjunctival epithelium through airlift culture, as evidenced by increased stratification, positive expression of K10 and K16, obviously increased K14, Ki67 and p63, and obviously declined or absent of Pax6 and MUC5AC. When cultured with AM, abnormal epidermal differentiation and hyper-proliferation of conjunctival epithelium were inhibited to a large extent, although MUC5AC expression diminished.Squamous metaplasia of conjunctival epithelium could be also reversed to nearly normal phenotype after 12 days co-culture with AM. Further more, AME exhibited similar activity in terms of preventing squamous metaplasia of conjunctival epithelium. Wnt signaling pathways were activated in conjunctival explants cultured under airlift manner, whiLe down-regulated when conjunctival explants were co-cultured with AM.CONCLUSIONS: Squamous metaplasia of conjunctiva can be created successfully and stablely by culturing conjunctiva tissues at an air-liquid interface ex vivo. AM can inhibit and reverse squamous metaplasia of conjunctiva effectively. AME can also effectively inhibit squamous metaplasia of conjunctiva. The inhibition of AM on squamous metaplasia of conjunctiva is possibly mediated by soluble elements of AM and inhibiting the activation of Wnt signaling pathway.This may shed new light on prevention and treatment for diseases with conjunctival squamous metaplasia.