The effect of hydroxyurea on rabbit subconjunctival fibroblast culture anduse of hydroxyurea in rabbits after glaucoma filtration surgery

In an in vitro study, rabbit subconjunctival fibroblasts were cultured and the effects of an antineoplastic drug, hydroxyurea (HU), on fibroblast prol iferation and fibroblast attachment was investigated. The effects of HU wer e compared with those of mitomycin C (MMC). Different concentrations of HU and MMC were added to culture medium. The HU doses which led to 50% of inhi bition (ID50) and the dose which led to about 90% of inhibition (subtoxic h igh dose, STHD) were determined to be 8 and 1,000 mu g/ml, respectively. ID 50 Of MMC and its STHD which led to about 100% inhibition were found to be 0.01 and 1 mu g/ml, respectively. Reversibility studies revealed that inhib ition disappeared depending on the dose and incubation period of both HU an d MMC. In an in vivo study, glaucoma filtration surgery (GFS) was performed in rabbits which were treated with HU (treatment group) and distilled wate r (control group). Tissue samples were taken from the subconjunctival area treated at 1 h, 1 day, 5 days and 30 days postoperatively. The biopsy speci mens were then placed in tissue culture media. Fibroblast outgrowth rates d etected in the HU group were found to be significantly lower than those in the control group in the specimens taken at the end of the first hour. The difference was significant on culture days 9-15 in the biopsy specimens tak en on day 1 while it was not significant in those ta ken on days 5 and 30.