Suppression of interleukin 1 α and interleukin 1 β in human limbal epithelial cells cultured on the amniotic membrane stromal matrix

Abstract

Aims - Amniotic membrane (AM) transplantation reduces inflammation in a variety of ocular surface disorders. The aim of this study was to determine if AM stroma suppresses the expression of the IL-1 gene family in cultured human corneal limbal epithelial cells. Methods - Human corneal limbal epithelial cells were cultured from limbocorneal explants of donor eyes on plastic or on the AM stroma. Transcript expression of IL-1α, IL-1β, IL-1 receptor antagonist (RA), and GAPDH was compared with or without addition of lipopolysaccharide to their serum-free media for 24 hours using RNAse protection assay (RPA). Their protein production in the supernatant was analysed by ELISA. Results - Expression of IL-1α and IL-1β transcripts and proteins was significantly reduced by cells cultured on the AM stromai matrix compared with plastic cultures whether lipopolysaccharide was added or not. Moreover, expression of IL-1 RA by cells cultured in the lipopolysaccharide-free medium was upregulated by AM stromal matrix. The ratio between IL-1 RA and IL-1α protein levels in AM cultures was higher than in plastic cultures. Conclusions - AM stromal matrix markedly suppresses lipopolysaccharide induced upregulation of both IL-1α and IL-1β. These data may explain in part the effect of AM transplantation in reducing ocular surface inflammation, underscoring the unique feature of the AM as a substrate for tissue engineering.