May 2006
Volume 47, Issue 13
Free
ARVO Annual Meeting Abstract  |   May 2006
Enzymatic Manipulation of the Vitreous Cavity by Microplasmin Affects Vitreous Oxygen Levels in Animal Models
Author Affiliations & Notes
  • P.A. Quiram
    Beaumont Hospital, Associated Retinal Consultants, Royal Oak, MI
  • V. Leverenz
    Oakland University, Eye Research Institute, Rochester, MI
  • R. Baker
    Oakland University, Eye Research Institute, Rochester, MI
  • L. Dang
    Oakland University, Eye Research Institute, Rochester, MI
  • M.T. Trese
    Beaumont Hospital, Associated Retinal Consultants, Royal Oak, MI
  • F.J. Giblin
    Oakland University, Eye Research Institute, Rochester, MI
  • Footnotes
    Commercial Relationships  P.A. Quiram, None; V. Leverenz, None; R. Baker, None; L. Dang, None; M.T. Trese, None; F.J. Giblin, None.
  • Footnotes
    Support  NIH Grant EY02027 and EY014803
Investigative Ophthalmology & Visual Science May 2006, Vol.47, 1486. doi:
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      P.A. Quiram, V. Leverenz, R. Baker, L. Dang, M.T. Trese, F.J. Giblin; Enzymatic Manipulation of the Vitreous Cavity by Microplasmin Affects Vitreous Oxygen Levels in Animal Models . Invest. Ophthalmol. Vis. Sci. 2006;47(13):1486.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose: : To determine if induction of an enzymatic–assisted posterior vitreous detachment (PVD) and vitreous liquefaction affects O2 concentration in the vitreous cavity.

Methods: : Either microplasmin (0.6 units) or hyaluronidase (25 units) was injected intravitreally into either guinea pigs or Brown Norway rats with the contralateral eye as a control. One week post injection, vitreal oxygen concentration was measured using a highly sensitive, platinum–based fluorophore O2 sensor (Oxford Optronix, Ltd.). In addition, control and microplasmin–injected animals were exposed to 100% oxygen by facemask, and vitreal O2 levels were measured over time. Scanning electron microscopy (SEM) was used to evaluate the vitreoretinal interface for the presence of a PVD.

Results: : Intravitreal injection of microplasmin significantly increased vitreal O2 concentration in guinea pigs (4–fold, p<0.05) and rats (2–fold, p<0.005) as compared to control eyes. Intravitreal injection of PBS or hyaluronidase revealed similar vitreal O2 levels as compared to controls. When the normal, control guinea pig was exposed to 100% O2 the mid–vitreal levels of O2 steadily increased to 55 mm Hg over 20 minutes with a slow return to baseline when switched to room air. When exposed to 100% O2, microplasmin–treated eyes showed an accelerated increase in oxygen levels reaching 80 mm Hg in 2 minutes. The results suggest that an intact vitreous cavity may act as a buffer against elevated blood oxygen levels. SEM showed smooth retinal surfaces in microplasmin–injected eyes, indicating the presence of a PVD which was not present in control eyes.

Conclusions: : Our results suggest that enzymatic–assisted PVD with microplasmin may increase vitreal O2 levels and increase O2 exchange within the vitreous cavity.

Keywords: vitreous • injection • oxidation/oxidative or free radical damage 
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