Nuclear light scattering, disulfide formation and membrane damage in lenses of older guinea pigs treated with hyperbaric oxygen

Giblin, Frank J.; Padgaonkar, Vanita A.; Leverenz, Victor R.; Lin, Lishan; Lou, Marjorie F.; Unakar, Nalin J.; Dang, Loan; Dickerson, Jaime E.; Reddy, Venkat N.

doi:10.1016/s0014-4835(05)80105-8

Cited by 131 publications

(113 citation statements)

References 56 publications

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“…4A). These results are in agreement with those obtained previously through biochemical analysis of lens supernatants, which showed increases in lens nuclear PSSP and protein/thiol mixed disulfides following HBO-treatment of guinea pigs (Giblin et al, 1995;Simpanya et al, 2005). Thus, possible artifactual production of -SS-occurring during lens homogenization in previous studies has been ruled out.…”

Section: Discussionsupporting

confidence: 93%

“…4A) was the result of PSSP formation. HBO-treatment has been reported not to produce increased levels of GSSG in the lens nucleus (Giblin et al, 1995). However, substantial amounts of protein-bound glutathione (PSSG) and protein-bound cysteine (PSSC) do accumulate in the nucleus following HBO-treatment (Giblin et al, 1995), and thus these compounds would have contributed to some extent to the observed O 2 -induced increase in nuclear -SS- (Fig.…”

Section: Discussionmentioning

confidence: 94%

“…However, since 90% of the -SH content of the guinea pig lens nucleus is PSH (Giblin et al, 1995), it is probable that the majority of the observed O 2 -induced increase in nuclear -SS- (Fig. 4A) was the result of PSSP formation.…”

Section: Discussionmentioning

confidence: 98%

“…The formation of lens protein disulfide (PSSP), leading to crosslinking and precipitation of lens crystallins, is a major factor in the development of nuclear cataract (Dische and Zil, 1951;Spector, 1984;Giblin et al, 1995) . 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-).…”

Section: Introductionmentioning

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: Discussionsupporting

confidence: 93%

Section: Discussionmentioning

confidence: 94%

Section: Discussionmentioning

confidence: 98%