Topical minoxidil for glaucoma filtration surgery in the rabbit

Studies evaluated the effect of topical minoxidil on the proliferation of limbal fibroblasts in rabbits following filtration surgery. New Zealand white rabbits underwent unguarded trabeculectomies in a masked, randomized, paired-design prospective study. Rabbits were treated topically every 3 hr around the clock for 1, 2 or 4 days post-operatively, with one drop of a 50-microliters solution containing either 20, 40 or 120 nM minoxidil or the vehicle alone. Another group of animals continued to receive 120 nM minoxidil topically every 8 hr for up to 10 days. Intraocular pressure (IOP), bleb appearance, signs of ocular toxicity and anterior chamber reaction were monitored. Animals were killed and tissues immediately surrounding the trabeculectomy ostium were removed and processed for vimentin detection by immunohistochemistry. Minoxidil, in 20 and 40 nM concentrations, did not induce a significant IOP reduction, nor prolonged bleb survival at any time point, and the changes in fibroblast counts between treated and control eyes were insignificant (P > 0.05). Fibroblast counts in the 120 mM minoxidil-treated eyes were significantly reduced by 42.6% within 24 hr compared to control (P < 0.001). This inhibitory effect remained for at least 2 days after surgery (P < 0.05), the critical period for scar formation. The blebs in this group remained consistently higher than in any other group, and some blebs survived for up to 8 days after surgery. IOP remained below preoperative level for at least 6 days in 50% of the eyes treated with 120 mM minoxidil (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)