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Induction of Posterior Vitreous Detachment in Rabbits by Intravitreal Injection of Tissue Plasminogen Activator Following Cryopexy

https://doi.org/10.1006/exer.1999.0772Get rights and content

Abstract

The purpose of this study was to generate intravitreal plasmin after intravitreal injection of tissue plasminogen activator (TPA) and cryopexy, and to assess its proteolytic effect on the vitreoretinal border region.Twenty-four hr after a mild cryopexy, 25 μg recombinant tissue plasminogen activator (TPA) was injected into the vitreous cavity, the fellow eye received an intravitreal injection of the same volume of buffered salt solution. Light, scanning and transmission electron microscopy was performed in 24 eyes that underwent vitrectomy 1 week later. Plasmin was measured prior and 2 hr after intravitreal TPA injection (4 eyes). Hyaluronic acid (8 eyes) and vitronectin (4 eyes) were measured 1 week after TPA- or BSS-injection and compared to untreated controls.

In all eyes treated with TPA, histopathologic examination by scanning and transmission electron microscopy demonstrated a complete detachment of the vitreous from the surface of the retina as well as from the posterior surface of the lens. After BSS-injection, vitreous cortex attachment to the retina was demonstrated in all eyes. Two hr after TPA-injection, plasmin increased to 9.75 mU ml-1(s.d.±2.3). Neither a decrease of hyaluronic acid nor an increase of transglutaminase, that might alter the vitreous structure leading to a collapse of the vitreous, were detected in treated eyes. There was no increase of vitronectin indicating proliferative activity.

A temporary breakdown of the blood–retinal barrier by cryopexy combined with intravitreal injection of TPA is a sufficient technique to induce a posterior vitreous detachment enzymatically. The method may be useful prior to mechanical vitrectomy.

References (34)

  • J.L. Gottlieb et al.

    The safety of intravitreal hyaluronidase

    Invest. Ophthalmol. Vis. Sci.

    (1990)
  • Hageman, G. S. and Rusell, S. R. (1994). Chondroitinase-mediated desinsertion of the primate vitreous body. Invest....
  • D.P. Han et al.

    Surgical excision of the attached posterior hyaloid

    Arch. Ophthalmol.

    (1988)
  • J.W. Harbour et al.

    Vitrectomy for diabetic macular edema associated with a thickened and taut posterior hyaloid membrane

    Am. J. Ophthalmol.

    (1995)
  • M. Harooni et al.

    Efficacy and safety of enzymatic posterior vitreous detachment by intravitreal injection of hyaluronidase

    Retina.

    (1998)
  • L. Hesse et al.

    Management of acute submacular hemorrhage using recombinant tissue plasminogen activator and gas

    Graefes Arch. Clin. Exp. Ophthalmol.

    (1999)
  • E.H. Jaccoma et al.

    Cryotherapy causes extensive breakdown of the blood-retinal barrier

    Arch. Ophthalmol.

    (1985)
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    Address correspondence to: Lutz Hesse, Department of Ophthalmology, Philipps-University, Robert-Koch-Str. 4, 35033 Marburg, FRG. Fax: +49-6421-2865678; E-mail: [email protected]

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