Abstract
Abstract: :
Purpose:Microplasmin is a recombinant protein, which contains the active enzymatic site of plasmin. It was shown to be capable of inducing a posterior vitreous detachment in several animal species (pig, rabbit, cat, monkey) as well as in human cadaver eyes. The current study was initiated to determine the effect of microplasmin on vitreous integrity, and to compare this effect to human plasmin. Methods:Fresh donor pig eyes were used in these experiments after removal of cornea and lens. These were incubated at room temperature or at 37°C for 2 hours with 125µg of microplasmin or 1U of plasmin in BSS+. Eyes were then injected with 0.1mL of a 2% sodium fluorescein solution, adjacent to the microplasmin injection site. Diffusion of fluorescein through the eye was digitally photographed over a 40 minute period. The extent of dye diffusion was measured as the maximal linear distance of stained vitreous seen through the corneal opening divided by the corneal diameter (LDU). Results:Control eyes injected with BSS+ show nearly no dye migration over a 40 minute period. Injection of microplasmin at room temperature lead to visible dye migration with an LDU value of 0.1 in 30 minutes. At 37°C, plasmin achieved an LDU of 0.1 in 20 minutes, while microplasmin gave a value of 0.15. Conclusion:Microplasmin modifies the integrity of vitreous leading to facilitated diffusion of fluorescein dye. This effect is temperature dependent and is more prominent than a comparative dose of plasmin.
Keywords: proteolysis • vitreous • pharmacology