Inhibition of Cell Proliferation by Mitomycin C Incorporated into P(HEMA) Hydrogels

Abstract

Abstract: : Purpose: Treatment with topical mitomycin C (MMC) is often used after trabeculectomy to attenuate the wound–healing response, especially in eyes at high risk for failure. This preliminary study examined the efficacy of a slow–release form of MMC for its ability to inhibit cell proliferation in vitro. Methods: MMC was incorporated into 1% P(HEMA) hydrogels using a redox polymerization method. For some experiments, unreacted low molecular weight components were removed from the hydrogels before the MMC was incorporated. Sterile disks (6 mm) of each polymer sample were affixed to 60 mm tissue culture dishes, and the dishes were subsequently inoculated with COS–1 cells or early passage human conjunctival fibroblasts. After 7 days in culture, the number of cells in each dish was determined using a dye–binding assay (Leavesley, DI et al, (1992) J. Cell. Biol. 117:1101). Cell morphology was assessed in replicate cultures after fixation and staining. Results: Hydrogels with unreacted low molecular weight components slowed cell proliferation and induced morphological changes. Early passage human conjunctival fibroblasts were more sensitive than COS–1 cells both to intrisinc contaminants in the hydrogels and to incorporated MMC. Once contaminants had been removed, MMC–loaded hydrogels inhibited conjunctival fibroblast proliferation in a dose–dependent fashion, with an IC₅₀ of ∼0.15 mg/g polymer. Conclusions: This study demonstrates that a slow–release form of MMC can inhibit cell proliferation in vitro. Future experiments will focus upon the efficacy of this polymer– bound form during in vivo wound healing.

Keywords: wound healing • pharmacology • proliferation