THE EFFECTS OF SUBCONJUNCTIVAL VERAPAMIL ON FILTERING BLEBS IN RABBITS

BACKGROUND AND OBJECTIVE: Verapamil is a calcium antagonist that has b een shown to modulate wound healing through multiple mechanisms. The w ound modulating effects of verapamil were studied in a rabbit model of filtering surgery. MATERIALS AND METHODS: Twenty New Zealand albino r abbits underwent a fistulizing procedure, with either verapamil or sal ine injected subconjunctivally daily for 6 days following surgery. The animals were sacrificed at 20 days after the fistulizing procedure. T he effectiveness of verapamil in modulating wound healing was evaluate d by bleb patency testing, histology, measurement of scar thickness, a nd counts of bromodeoxyuridine (BrdU)-labeled cells at the sclerostomy site. RESULTS: The group treated with verapamil had a 44% patency rat e compared with 10% in the control group (P <.05), a mean scar thickne ss of 195.96 +/- 68 mu m compared with 313.55 +/- 110.4 mu m in the co ntrol group (P<.02), and a mean BrdU-labeled cell count of 15.5 +/- 14 .7 compared with 26.3 +/- 17.0 in the control group (P =.002). CONCLUS ION: Verapamil was effective in reducing scar formation at the scleros tomy site, At the doses administered, verapamil appeared to modulate w ound healing in filtering blebs in the rabbit model. Further studies a re needed to determine the dose-response and the efficacy of the drug in nonhuman primates.