Abstract
Abstract: :
Purpose: To evaluate the toxic levels of suramin to compare with mitomycin–C (MMC) –as subconjunctival adjunctive agents in trabeculectomy– by investigating the damage in the ciliary epithelium of the rabbit eye. Methods: Thirty–two New Zealand albino rabbits were randomly distributed into 2 equal groups to receive either suramin or MMC subconjunctivally in the right eye. The groups were further divided into 4 subgroups according to pre–scheduled enucleation day (1, 3, 7 and 28th days). Two rabbits injected with balanced salt solution served as controls. Suramin group received 200, 300, 400 and 800 mg/ml injections, and MMC group received 0.2, 0.3, 0.4 and 0.8 mg/ml injections at 12 o’clock position on the first day of the study. The rabbits were sacrificed using IV ketamine HCl 150 mg/kg after enucleation was completed under general anesthesia. Then the globe was vertically bisected and one half was placed in 10% formaldehyde for apoptosis evaluation under light microscopy. The other half was placed in 2.5% formaldehyde for morphologic evaluation with transmission electron microscope (TEM). Results: The pathologic investigation revealed apoptosis in only 4 specimens. All apoptotic specimens were from the MMC group, but there was no relation of apoptosis with a particular MMC concentration. The morphologic evaluation with TEM showed that 200 mg/ml suramin and 0.2 mg/ml MMC did not cause irreversible tissue damage in the ciliary epithelium. Higher concentrations with MMC resulted in rapid and serious tissue damage in the ciliary epithelium, whereas the damage was present with suramin in excess of 200 mg/ml, but morphologically not as severe as in MMC group. Conclusions: Suramin 200 mg/ml and MMC 0.2 mg/ml seem to be non–toxic to the ciliary body in rabbit eye. Concentrations higher than these values caused irreversible damage.
Keywords: drug toxicity/drug effects • ciliary body • microscopy: electron microscopy