Effects of cyclosporin A on human conjunctival fibroblasts

objective: To evaluate the effects of cyclosporin A (CsA) on cytokine and/o r collagen production, cell growth, and apoptosis in conjunctival fibroblas t cultures. Methods: Fibroblast cultures derived from normal subjects and patients with vernal keratoconjunctivitis and pemphigoid were exposed to different conce ntrations of CsA for either 24 hours or 30 days. The effects were evaluated by the colorimetric MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazo lium bromide) test to assess cell proliferation, and by the measurement of procollagen I (PIP) and procollagen III (PIIIP) cytokines and total protein in culture medium. CsA-induced apoptosis was assessed by fluorescence-acti vated cell sorter analysis. Results: After 24 hours of exposure to doses of CsA of more than 10 mug/mL, cell proliferation and migration were significantly reduced. Cyclosporin A reduced PIP and interleukin 1 (IL-1) production in a dose-dependent manner . Interleukin 6 and IL-8 were increased by 10 mug/mL of CsA, whereas transf orming growth factor P, PIIIP, and total protein were unaffected. Cyclospor in A exposure induced apoptosis in a time- and dose-dependent manner. Long- term exposure to CsA reduced IL-6 but did not modify PIIIP production. Conclusion: Exposure to CsA directly modified fibroblast behavior. Clinical Relevance: Cyclosporin A ability to accelerate apoptosis in clinic ally fibrotic tissues may prove to be therapeutic and useful in hyperprolif erative conjunctival disorders.