Delay of uv-induced eye lens protein damage in guinea pigs by dietary ascorbate

Blondin, Joanne; Baragi, Vijaykumar M.; Schwartz, Edith R.; Sadowski, James A.; Taylor, Allen

doi:10.1016/s0748-5514(86)80010-1

Cited by 75 publications

(23 citation statements)

References 34 publications

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“…The results are in good agreement with experiments in which dietary ascorbic acid was able to delay or prevent protein damage during UV irradiation [8,9], Since the ascorbic-acid concentration in the pro tein solution of the experimental animals was higher than that in the control (experi mental: 36 pg/ml, control: 15 pg/ml), an ad ditional experiment was carried out to inves tigate the influence of added ascorbic acid in the protein solution. An appropriate quan tity of ascorbic acid was added to the protein solution of the control lens to give a concen tration that was comparable to the experi mental lenses.…”

Section: Resultssupporting

confidence: 83%

“…The results of the present study and pre vious work of other authors [6][7][8][9] strongly suggest that ascorbic acid is able to protect lens proteins against UV-, sunlight-and heat-induced damage. This in turn suggests that ascorbic acid may be able to protect lens components against cataract-like and agerelated changes.…”

Section: Resultssupporting

confidence: 74%

“…Since ascorbic acid is an antioxidant, the function of ascor bic acid at such high concentrations may be to protect the eye against oxidative stress. Ascorbic acid in amounts comparable to those in the aqueous humor was able to attenuate light-induced lens damage [6,7], An in vitro study showed that damage of water-soluble rabbit lens proteins during UV light exposure was prevented by high levels of added ascorbic acid [8], Dietary ascorbic acid could delay UV-induced eye lens pro tein damage in guinea pigs [9]. Levels of ascorbic acid in the cornea and the lens of buphthalmic rabbits were significantly lower than in normal rabbits [10].…”

Section: Introductionmentioning

confidence: 99%

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Effect of Dietary Ascorbic Acid on Heat-Induced Eye Lens Protein Damage in Guinea Pigs

Tsao¹,

Xu²,

Young³

1990

Ophthalmic Res

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The effect of large intake of dietary ascorbic acid on heat-induced eye lens protein damage has been studied. Male guinea pigs of the Hartley strain were used. Ascorbic acid was administered to the experimental animals in the drinking water. The mean daily ascorbic acid intakes for the control and experimental animals were 10 and 366 mg/kg body weight, respectively. The ascorbic acid level in the lens of the experimental animals was significantly higher than in the controls, but no differences in the content of water-soluble lens proteins were observed. When a solution of water-soluble protein was incubated at 60 ° C, insoluble aggregates were formed. The loss of water-soluble proteins from the lens of the experimental animals was significantly less than that of the controls. The results indicated that large quantities of dietary ascorbic acid were able to protect lens constituents against heat-induced damage.

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Section: Resultssupporting

confidence: 83%

Section: Resultssupporting

confidence: 74%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effect of Dietary Ascorbic Acid on Heat-Induced Eye Lens Protein Damage in Guinea Pigs

Tsao¹,

Xu²,

Young³

1990

Ophthalmic Res

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“…[4][5][6]. However, few in vivo models of cataract are available in animals which require ascorbate and which mimic the cataract observed in humans.…”

Section: Introductionmentioning

confidence: 99%

“…This also presented an opportunity to use guinea pigs as a model for cataract. With cataractous guinea pigs, it would be possible to test relationships between ascorbate and cata ract, since (1) guinea pigs are one of the few laboratory animals that, like humans, require ascorbate, and (2) ascorbate levels in guinea pig tissues (including eye) can be regulated by dietary intervention [11,12], Furthermore, these relationships are of interest, since pre liminary data indicate that enhanced dietary ascorbate is associated with diminished cata ractlike damage in guinea pigs [6], with de layed cataract in selenite-stressed mice [13], and with diminished cataract risk in humans [14,15]. Thus, the acetone cataract model appeared a very attractive tool.…”

Section: Introductionmentioning

confidence: 99%

Relationships between Acetone, Cataracts, and Ascorbate in Hairless Guinea Pigs

Taylor¹,

Smith²,

Palmer³

et al. 1993

Ophthalmic Res

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Acetone is one of the most commonly used industrial solvents. Recent literature indicated that in guinea pigs, but not rabbits, acetone is cataractogenic and that elevated acetone exposure is also associated with depressed aqueous ascorbate levels. Other work indicated that aqueous and lens levels of ascorbate are closely linked and that depressed ascorbate status is related to cataract. Taken together, these papers suggested that acetone exposure, depressed ascorbate levels, and cataract are related, possibly causally. While the possibility that acetone is cataractogenic presented a major health concern, it also presented an opportunity to develop a new model of cataract in which hypotheses regarding anticataractogenic effects of ascorbate could be tested. Albino hairless guinea pigs are immunocompetent animals derived from albino Hartley guinea pigs. Animals were fed diets containing low (4.9 mg/day) and high (55 mg/day) levels of ascorbate. This resulted in distinct groups of animals, one with high tissue ascorbate levels and the other with low, but nonscorbutic ascorbate levels. The tissue levels of ascorbate and the relationship between tissue ascorbate levels and dietary intake indicate that with respect to ascorbate uptake, transport, and concentration, these animals are identical to the standard albino Hartley animals. Daily exposure to acetone was extended for 6 months, with a total applied dose of 65 ml. Absorption of the solvent was maximized by the use of hairless animals. Despite exposure of the animals to higher levels of acetone, in no case (n = 20) were cataracts observed over a 2-year period. This is consistent with results using rabbits. The data show that the hairless guinea pig is a fine model for studies in which ascorbate bioavailability is of importance. However, other models to test the cataractogenic potential of acetone and anticataract effects of ascorbate are needed.

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