Korean J Ophthalmol.  2004 Jun;18(1):35-40. 10.3341/kjo.2004.18.1.35.

Long-term Effect of Plasmin on the Vitreolysis in Rabbit Eyes

• Kim NJ
• Yu HG
• Yu YS
• Chung H

• KMID: 1115781
• DOI: http://doi.org/10.3341/kjo.2004.18.1.35

Abstract

The aim was to investigate the proteolytic activity of plasmin and its long-term complications. Plasmin was injected into the vitreous cavity of rabbits' eyes. Slit lamp biomicroscopy and electroretinography were performed. Rabbits were serially sacrificed at four months, and globes fixated and prepared for light and transmission electron microscopy. In both the plasmin-injected and control eyes, electroretinography showed a transient decrease in the amplitude, but this recovered to the baseline level in a week. Under the light microscope, the plasmin-treated eyes had a smooth retinal surface, implying separation of the vitreous cortex from the retina. In the control eyes, the collagen fibers remained on the retinal surface. By transmission electron microscopy, the plasmin-treated eyes showed a vitreous-free retinal surface, but no vitreoretinal separation was observed in the control eyes. Plasmin induces a cleavage between the vitreous and the internal limiting membrane, with no long-term complications, so may be a useful pharmacologic adjunct to vitrectomy.

Keyword

internal limiting membrane; plasmin; posterior vitreous detachment

MeSH Terms

Animals
Electroretinography
Fibrinolysis/*drug effects
Fibrinolytic Agents/*pharmacology
Injections
Plasmin/*pharmacology
Rabbits
Research Support, Non-U.S. Gov't
Retina/drug effects/physiology
Vitreous Body/*drug effects
Vitreous Detachment/*chemically induced/pathology

Figure

• 

  Fig. 1 A: Electroretinograms of a control eye (PBS injection). B: Electroretinograms of a plasmin-treated eye. The PBS- and plasmin-injected eyes show decreased amplitude in the ERGs recorded on days 1 and 3. However by the 7th day post injection, the amplitude of the ERGs has recovered, with no difference from that of the baseline ERGs. These findings were maintained 4 months after the injection.

• 

  Fig. 2 A: light micrograph of a control eye 2 months after a PBS injection. Note the irregular, ragged retinal surface (PAS, ×400). B: light micrograph of a plasmin-treated eye 2 months post injection. Note the clear, smooth retinal surface (PAS, ×400).

• 

  Fig. 3 A: Transmission electron micrograph of a control eye 2 months after a PBS injection. Note the persistent cortical vitreous attached to the internal limiting membrane (arrowhead). (original magnification ×46,000). B: Transmission electron micrograph of a plasmin-treated eye 2 months post injection. Note the smooth internal limiting membrane (original magnification ×46,000).

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