Document Detail


High infusion pressure in conjunction with vitreous surgery alters the morphology and function of the retina of rabbits.
MedLine Citation:
PMID:  17403020     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
PURPOSE: To investigate the effects of high infusion pressure in conjunction with pars plana vitrectomy (PPV) on retinal morphology and function in rabbits. METHODS: Pars plana vitrectomy was performed under urethane (0.8 mg/kg) anaesthesia in the right eye of albino rabbits following phacoemulsification and aspiration (PEA). The left eyes were not touched. After PEA, the animals were divided into two groups. In six eyes, intraocular pressure (IOP) was increased to 80 mmHg for 30 mins (high-pressure group) and in five eyes IOP was maintained at 40 mmHg for 30 mins (low-pressure group). The IOPs were regulated by the height of the bottle of balanced salt solution (BSS) and monitored with a pressure transducer. After the pressure elevation, vitreous fluid was collected to measure the glutamate concentration. Then, PPV was performed for 15 mins in both groups under an infusion pressure of 40 mmHg. In five additional rabbits, PEA alone was performed in the right eye, and vitreous fluid was collected (PEA group). Functional alterations were assessed by recording visual evoked potentials (VEPs) and electroretinograms (ERGs). Ten days after the IOP changes, the animals were killed with intravenous pentobarbital sodium and the eyes were prepared for histological analysis. Damage to retinal ganglion cells (RGCs) was quantified by counting the number of cells in the ganglion cell layer (GCL). The contralateral eyes in the high-pressure group served as controls (n = 6). RESULTS: The mean implicit time (IT) of the VEPs in the high-pressure group was significantly longer than that before the IOP elevation, by 114-124% (p < 0.05, paired t-test), and also than that of control eyes (p < 0.05, anova followed by t-test). No significant changes in the VEPs were detected in either the low-pressure group or the PEA group. There were significantly fewer cells in the GCL in the high-pressure group (24.7/mm) than in the control animals (41.4/mm; p < 0.05, Dunnett's test). The number of cells in the GCL in the low-pressure and PEA groups did not significantly differ to that in the controls. The amplitudes of the ERG a- and b-waves were not significantly changed (p > 0.05, paired t-test). CONCLUSIONS: These results suggest that high infusion pressure in conjunction with PPV leads to morphological and functional changes in the retina. The absence of ERG changes and presence of VEP changes suggest that these changes were due to damage to RGCs, which supports the morphological observations.
Authors:
Masahiro Minami; Hidehiro Oku; Takashi Okuno; Masayuki Fukuhara; Tsunehiko Ikeda
Publication Detail:
Type:  Journal Article     Date:  2007-04-02
Journal Detail:
Title:  Acta ophthalmologica Scandinavica     Volume:  85     ISSN:  1395-3907     ISO Abbreviation:  Acta Ophthalmol Scand     Publication Date:  2007 Sep 
Date Detail:
Created Date:  2007-08-27     Completed Date:  2007-10-23     Revised Date:  2008-03-17    
Medline Journal Info:
Nlm Unique ID:  9507578     Medline TA:  Acta Ophthalmol Scand     Country:  Denmark    
Other Details:
Languages:  eng     Pagination:  633-9     Citation Subset:  IM    
Affiliation:
Department of Ophthalmology, Osaka Medical College, Osaka, Japan.
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MeSH Terms
Descriptor/Qualifier:
Animals
Cell Count
Drainage
Electroretinography
Evoked Potentials, Visual / physiology
Glutamic Acid / metabolism
Intraocular Pressure*
Male
Ocular Hypertension / complications*
Phacoemulsification
Rabbits
Retinal Diseases / etiology,  physiopathology*
Retinal Ganglion Cells / pathology*
Vitrectomy*
Vitreous Body / metabolism,  surgery*
Chemical
Reg. No./Substance:
56-86-0/Glutamic Acid

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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