Suramin modulates wound healing of rabbit conjunctiva after trabeculectomy: comparison with mitomycin C

To investigate and compare the effects of suramin and mitomycin C on conjunctival wound healing after trabeculectomy in a rabbit model.

Thirty New Zealand White rabbits were divided into three groups, and trabeculectomy was performed on the left eyes under general anesthesia. During the surgery, suramin (250 mg/ml) and mitomycin C (0.4 mg/ml) were applied to the scleral flap site for 2 minutes in groups 1 and 2, respectively. The control animals (group 3) received no pharmacological treatment during trabeculectomy. Intraocular pressure (IOP) measurements were recorded before surgery and every 3 days after the operation, starting from postoperative day 1. Three animals from each group were sacrificed on days 15, 20, and 25, yielding a total of 27 eyes for histopathological study. Each specimen was histochemically and immunohistochemically (CD3, CD20, CD68, and collagen III) evaluated, and graded.

Bleb failure time was significantly longer in both the suramin (15.0 +/- 4.7 days) and mitomycin C (16.7 +/- 5.1 days) groups than in the controls (10.3 +/- 4.2 days) (p < 0.05). Starting from postoperative day 9, the IOP in the suramin and mitomycin C groups was significantly lower than that in the control group (p < 0.05). This difference continued to be significant until day 18 for the suramin group, and until day 24 in the mitomycin C group. Histopathological evaluation showed lower degrees of cellularity, fibrosis, collagen III deposition, and CD3 density in the suramin- and mitomycin C-treated eyes compared to control eyes at all time points (p < 0.05). There was also no significant difference between the suramin and mitomycin C groups concerning these histopathological findings and CD3 density (p > 0.05). Although there were trends towards reduced mean elastic fiber deposition and lower CD20 and CD68 density in both groups of treated eyes, the differences between the treated and control groups were not significant (p > 0.05).

The results of the current study suggest that suramin has beneficial effects on wound healing in glaucoma surgery, and effectively prolongs bleb survival in rabbits. Suramin may be a promising alternative to anti-metabolite therapy in glaucoma surgery.