Aggregation of Lens Crystallins in an In Vivo Hyperbaric Oxygen Guinea Pig Model of Nuclear Cataract: Dynamic Light-Scattering and HPLC Analysis

Simpanya, Mukoma F.; Ansari, Rafat R.; Suh, Kwang I.; Leverenz, Victor R.; Giblin, Frank J.

doi:10.1167/iovs.05-0843

Cited by 63 publications

(64 citation statements)

References 68 publications

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“…As in our previous studies (Borchman et al, 2000;Simpanya et al, 2005), increased lens nuclear light scattering was also observed in the present study after 50 treatments of the guinea pigs with HBO, compared to age-matched controls, and the level of scatter intensified after 85 treatments. Since this type of slit-lamp data has been shown previously (Borchman et al, 2000;Simpanya et al, 2005), the results have not been repeated here.…”

Section: Resultssupporting

confidence: 92%

“…Age-matched control guinea pigs were included with each group of O 2 -treated animals. Both 50 and 85 HBO-treatments have been shown to produce an increased level of lens nuclear light scattering in guinea pigs, compared to age-matched controls (Borchman et al, 2000;Simpanya et al, 2005). A two-fold increase in lens focal length variability was observed after 70 treatments of guinea pigs with HBO (Bantseev et al, 2004).…”

Section: Methodsmentioning

confidence: 99%

“…During this time, the lenses of the guinea pigs were examined carefully by slit-lamp biomicroscopy, and animals with lens opacities were excluded from the study. Procedures used to treat guinea pigs with HBO have been described in detail previously (Simpanya et al, 2005). Each experimental animal was exposed to 2.5 atm absolute (ATA; 22.3 psig [pounds per square inch gauge] or 51 ft. of seawater) of 100% O 2 for 2.5 hr periods, three times per week on alternate days.…”

Section: Methodsmentioning

confidence: 99%

“…Recent studies have linked molecular oxygen (O 2 ) with lens nuclear opacity (Holekamp et al, 2005;Simpanya et al, 2005), and it is possible that O 2 is a precursor to a more active, harmful species within the lens that can generate disulfide (-SS-). We treat guinea pigs with hyperbaric oxygen (HBO) in order to investigate events leading to nuclear cataract, and have used this technique to demonstrate an association between O 2 -induced lens nuclear light scattering and an increase in the level of PSSP (Giblin et al, 1995;Simpanya et al, 2005). However, in these studies, PSSP analyses were conducted in supernatants of lens homogenates, a procedure that can possibly lead to artifactual production of -SS-.…”

Section: Introductionmentioning

confidence: 99%

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Raman spectroscopic evidence for nuclear disulfide in isolated lenses of hyperbaric oxygen-treated guinea pigs

Gosselin

Kapustij

Venkateswaran

et al. 2007

Experimental Eye Research

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Our laboratory treats guinea pigs with hyperbaric oxygen (HBO) as a model for investigating the formation of nuclear cataract. Previous analyses of lens supernatants using this model have shown an increase in disulfide (-SS-) and loss of sulfhydryl (-SH) in the lens nucleus of O 2 -treated animals. In this paper, we have used the non-invasive technique of Raman spectroscopy to confirm these findings in intact, freshly-excised lenses. Guinea pigs were treated 3 times per week with HBO for a total of 50 (4 months of treatment) or 85 (7 months of treatment) times to induce an increased level of lens nuclear light scattering. Intact lenses were analyzed by Raman spectroscopy using a 514.5 nm laser and collecting the scattered light in a 90° geometry. The laser beam was focused either in the lens nucleus or equatorial cortex. Changes in the levels of -SS-(503 cm −1 ) and -SH (2577 cm −1 ) vibrations were measured. Raman spectra were analyzed by fitting Lorentzian profiles to the observed data in the -SS-and -SH regions. -SS-levels in the O 2 -treated nucleus were found to have increased by a factor of 2.1 (p=0.0001) and 2.5 (p=0.001) after 50 and 85 HBO treatments, respectively, compared to age-matched controls. Based on previous biochemical analyses, the -SSincrease was due mainly to the formation of protein disulfide (PSSP) with contribution also from protein/thiol mixed disulfides, but not from oxidized glutathione. -SH levels in the O 2 -treated nucleus decreased by 13% (p=0.007) and 35% (p=0.001) after 50 and 85 HBO treatments, respectively, compared to age-matched controls. No significant increase in -SS-or loss of -SH was observed in the lens cortex of the O 2 -treated guinea pigs. The Raman spectroscopy results rule out the possibility that artifactual production of -SS-and loss of -SH occurred during homogenization of lenses in previous studies. The data provide additional evidence to support a link between O 2 , disulfidecrosslinking of lens crystallins in the nucleus, and nuclear cataract.

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Section: Resultssupporting

confidence: 92%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Raman spectroscopic evidence for nuclear disulfide in isolated lenses of hyperbaric oxygen-treated guinea pigs

Gosselin

Kapustij

Venkateswaran

et al. 2007

Experimental Eye Research

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“…Oxidation of α-crystallin is linked to cataractogenesis, in particular oxidation of cysteine residues (Garner and Spector, 1980). Aggregation of lens crystallin has been demonstrated by Simpanya et al (2005) in guinea pigs treated with hyperbaric oxygen (higher than atmospheric oxygen tension) three times weekly for 7 months. In this study HPLC-isolated aggregates contained αA-but not αB-crystallin, which is devoid of -SH groups and thus does not participate in disulfide cross-linking.…”

Section: Mitochondrial Ros Systems and Cataractmentioning

confidence: 99%

Mitochondrial function and redox control in the aging eye: Role of MsrA and other repair systems in cataract and macular degenerations

Brennan¹,

Kantorow²

2009

Experimental Eye Research

162

141

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Oxidative stress occurs when the level of prooxidants exceeds the level of antioxidants in cells resulting in oxidation of cellular components and consequent loss of cellular function. Oxidative stress is implicated in wide range of age related disorders including Alzheimer's disease, Parkinson's disease amyotrophic lateral sclerosis (ALS), Huntington's disease and the aging process itself (Lin and Beal, 2006). In the anterior segment of the eye, oxidative stress has been linked to lens cataract (Truscott, 2005) and glaucoma (Tezel, 2006) while in the posterior segment of the eye oxidative stress has been associated with macular degeneration (Hollyfield et al., 2008). Key to many oxidative stress conditions are alterations in the efficiency of mitochondrial respiration resulting in superoxide (O 2 -) production. Superoxide production precedes subsequent reactions that form potentially more dangerous reactive oxygen species (ROS) species such as the hydroxyl radical (˙OH), hydrogen peroxide (H 2 O 2 ) and peroxynitrite (OONO -). The major source of ROS in the mitochondria, and in the cell overall, is leakage of electrons from complexes I and III of the electron transport chain. It is estimated that 0.2-2% of oxygen taken up by cells is converted to ROS, through mitochondrial superoxide generation, by the mitochondria (Hansford et al., 1997). Generation of superoxide at complex I and III has been shown to occur at both the matrix side of the inner mitochondrial membrane and the cytosolic side of the membrane (Kakkar and Singh 2007). While exogenous sources of ROS such as UV light, visible light, ionizing radiation, chemotherapeutics, and environmental toxins may contribute to the oxidative milieu, mitochondria are perhaps the most significant contribution to ROS production affecting the aging process. In addition to producing ROS, mitochondria are also a target for ROS which in turn reduces mitochondrial efficiency and leads to the generation of more ROS in a vicious self-destructive cycle. Consequently, the mitochondria have evolved a number of antioxidant and key repair systems to limit the damaging potential of free oxygen radicals and to repair damaged proteins (Figure 1.0). The aging eye appears to be at considerable risk from oxidative stress. This review will outline the potential role of mitochondrial function and redox balance in age-related eye diseases, and detail how the methionine sulfoxide reductase (Msr)

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Clinical Detection of Precataractous Lens Protein Changes Using Dynamic Light Scattering

et al. 2008

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Aggregation of Lens Crystallins in an In Vivo Hyperbaric Oxygen Guinea Pig Model of Nuclear Cataract: Dynamic Light-Scattering and HPLC Analysis

Abstract: The results indicate that molecular oxygen in vivo can induce the cross-linking of guinea pig lens nuclear crystallins into large disulfide-bonded aggregates capable of scattering light. A similar process may be involved in the formation of human nuclear cataract.

Cited by 63 publications

References 68 publications

Raman spectroscopic evidence for nuclear disulfide in isolated lenses of hyperbaric oxygen-treated guinea pigs

Raman spectroscopic evidence for nuclear disulfide in isolated lenses of hyperbaric oxygen-treated guinea pigs

Mitochondrial function and redox control in the aging eye: Role of MsrA and other repair systems in cataract and macular degenerations

Clinical Detection of Precataractous Lens Protein Changes Using Dynamic Light Scattering

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