Abstract
Abstract: :
Purpose: Cornea epithelial cells are always affected by various physical factors, such as, temperature, humidity, ultraviolet irradiation, and airflow. Desiccation is significantly affected on these cellular conditions. We investigated the influence of desiccation on inflammatory cytokine production in corneal cells using human corneal epithelial (CEPI) cell line and dry eye model rats. Methods: CEPI was grown in keratinocyte growth medium 2 (KGM2) to approximately 80% confluence in dishes. The medium is discarded by aspiration and plates were left for 0 to 30 minutes with opening the cover to dry the cells (short term desiccation). KGM2 was poured into the dishes. Fifteen minutes later, the medium was collected to measure the concentration of the cytokines in medium by EIA. Viability of the cells was estimated with alamer Blue. To study the effect of long term desiccation, we use transwell (Corning Inc., corning, NY). CEPI was grown on membrane of transwell. KGM2 in upper–layer was discarded to dry CEPI. After desiccation, viability of the cells, expression of cytokines, and concentration of the cytokines in medium were measured. The expression of cytokines in cornea of dry eye model rat was measured by real time PCR. Results: In short term desiccation, CEPI started to die after 20 minute of desiccation. Secretion of IL–6 from CEPI increased by 15–20 minutes desiccation but that of TNFα did not change. In long term desiccation, secretion of IL–6 and IL–8 from CEPI increased but that of TNFα did not change. Expression of IL–6 was also increased. In dry eye model rat, the mRNA of IL–6 obtained from cornea also increased significantly, but that of TNFα did not change. Conclusions: The cell death induced by desiccation is suggested to related IL–6 and IL–8 secretion but not TNFα.
Keywords: cornea: epithelium • cytokines/chemokines • cornea: tears/tear film/dry eye