Oxidation, antioxidants and cataract formation: a literature review

Williams, David L.

doi:10.1111/j.1463-5224.2006.00498.x

Cited by 79 publications

(58 citation statements)

References 75 publications

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“…Because the turnover rate of crystallins is very slow compared to many other organs, the reversal of protein modification by several factors is slow and it can be thought to induce cataract ( 2 ). The mechanism of cataractogenesis is not clear, but the osmotic stress and the oxidative stress have been thought of as the major causes of cataractogenesis ( 3 ). The osmotic stress by excessive accumulation of sorbitol formed from elevated glucose has been reported as the main mechanism of diabetic cataract.…”

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confidence: 99%

Taurine Prevents Oxidative Damage of High Glucose-Induced Cataractogenesis in Isolated Rat Lenses

Son

Kim

Kwon

2007

J Nutr Sci Vitaminol

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Summary Diabetic cataract is an ocular disease represented as blindness by lens opacification. Oxidative as well as osmotic stress caused by accumulation of polyols within the lens has been shown to be associated with glucose-induced cataractogenesis. Taurine has an antioxidant capacity and its level in diabetic cataractous lens is markedly decreased. Therefore, we investigated whether taurine is a part of antioxidative defense mechanism involved in protecting the lens against high glucose-induced oxidative stress and tissue damage. Lenses were isolated from male Sprague-Dawley rats weighing about 180-200 g and cultured in high glucose medium (55.6 m M ) for 6 d as a model of high glucose-induced cataractogenesis. To investigate the antioxidative effect of taurine, 30 m M taurine was added in normal medium for 2 d before the addition of high glucose. The culture of lenses in high glucose medium increased the weight and opacity of lenses of and the carbonylated protein level, and decreased glutathione (GSH) content. Although there were no significant effects of taurine on the weight or opacity of lenses, pretreatment of lenses with 30 m M taurine significantly reversed the level of protein carbonylation and GSH to those of controls. Therefore, taurine might spare GSH and protect the lens from oxidative stress induced by a high concentration of glucose. Key Words cataract, oxidative stress, glucose, taurine, GSH Diabetic cataract, one of the secondary complications of diabetes, is the major cause of blindness due to the opacification of the lens. The lens is the only transparent organ in the body and focuses light on the retina. The main components of the lens are about 63% of water and 35% of protein which is composed of over 90% of crystallins ( 1 ). Because the turnover rate of crystallins is very slow compared to many other organs, the reversal of protein modification by several factors is slow and it can be thought to induce cataract ( 2 ). The mechanism of cataractogenesis is not clear, but the osmotic stress and the oxidative stress have been thought of as the major causes of cataractogenesis ( 3 ). The osmotic stress by excessive accumulation of sorbitol formed from elevated glucose has been reported as the main mechanism of diabetic cataract. But several studies indicated that oxidative stress may be the major contributor to a sugar-induced cataractogenesis, which can be prevented or attenuated by antioxidants such as vitamin E ( 4 ), glutathione (GSH) ( 5 ), vitamin C ( 6 ), and Nacetylcysteine ( 7 ). It is shown that levels of major antioxidants were reduced in cataractogenesis by osmotic compensation against sorbitol accumulation ( 8 , 9 ). Along with the loss of antioxidants, the increase of glucose concentration in the lens would result in higher free radical generation and nonenzymatic glycation ( 10 , 11 ).Taurine (2-aminoethanesulfonic acid) has a sulphonic acid group, which is not found in other amino acids. Because this amino acid is not used for the synthesis of protein, it is abundant as a fre...

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confidence: 99%

Taurine Prevents Oxidative Damage of High Glucose-Induced Cataractogenesis in Isolated Rat Lenses

Son

Kim

Kwon

2007

J Nutr Sci Vitaminol

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“…The chosen genes are interesting candidates for the use in studies on the molecular mechanisms leading to cataract development in Atlantic salmon. Glutathione reductase (GR), glutathione S-transferase (GST), and manganese superoxide dismutase (Mn-SOD) are involved in the elimination of reactive oxygen species (ROS) caused by oxidative stress (Fridovich 1995;Lou 2003;Raza et al 2002), one of the main factors involved in cataract formation (Truscott 2005;Williams 2006). Heat shock protein 70 (HSP70) and metallothionein B (MT-B) are known to be induced by multiple types of stresses (Iwama et al 1998;Kägi 1993).…”

Section: Discussionmentioning

confidence: 99%

Optimisation of gene expression analysis in Atlantic salmon lenses by refining sampling strategy and tissue storage

Tröβe

Waagbø

Breck³

2010

Fish Physiol Biochem

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Analysis of gene expression in the lens is one of the analytical tools employed to investigate cataract formation in Atlantic salmon (Salmo salar L.). High quality RNA preparations are an essential prerequisite for gene expression analysis. The first aim of the present study was to investigate the possible effects of two methods of tissue preservation on the quality of RNA extracted from Atlantic salmon lenses. RNA was extracted from lenses either stored in RNAlater or flash-frozen in liquid nitrogen. Both tissue preservation methods yielded RNA of similarly high quality. The second aim was to examine if stress related to fish handling and the choice of anaesthesia during the sampling procedure affected gene expression in the lens. Six sampling procedures were tested on groups of sea water adapted Atlantic salmon smolt. Fish were either killed instantaneously (control group) or sampled after 30 min anaesthetised with isoeugenol, after 30 min without anaesthesia, after 120 min anaesthetised with isoeugenol, after 120 min with 15 min anaesthesia with metacaine or after 120 min without anaesthesia. The expression levels of specific genes, of special interest in the study of molecular mechanisms of cataractogenesis, were analysed in lenses by real-time RT-PCR. Fish not anaesthetised had significantly increased levels of heat shock protein 70 (HSP70) mRNA after 30 min compared to the control group. Glutathione reductase (GR) and manganese superoxide dismutase (Mn-SOD) were expressed at significantly lower levels in groups of Atlantic salmon sampled after 120 min anaesthetised with isoeugenol or metacaine, and anaesthetised with isoeugenol, metacaine or without anaesthesia, respectively. The same expression patterns were found in corresponding gill tissues for these two antioxidant genes. In conclusion, preservation in liquid nitrogen instead of RNAlater is recommended due to practical conditions in RNA extraction. A quick sampling protocol with the use of anaesthetics and not exceeding 30 min should be preferred to avoid effects of the sampling procedure on lens gene expression in Atlantic salmon.

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“…This preoxidant and other free radicals generated through auto-oxidation of sugars lead to oxidative stress (Jyothi et al, 2003;Marsili et al, 2004;Gupta et al, 2009) to which the lens is highly susceptible (Sasikala et al, 2010). Previous studies established oxidative stress as a triggering factor in the development of cataract (Williams, 2006) with augmentation of the antioxidant defenses of the lens seen to prevent or delay cataractogenesis (Spector, 1995).…”

Section: Discussionmentioning

confidence: 99%

“…However, risk factors such as socio-economic/educational level, metabolic disorders like diabetes, long-term use of steroids (Jobling and Augusteyn, 2002;Shakil et al, 2008), smoking (Eman and Elabrak, 2011), nutrition, excessive exposure to sunlight (Zarina et al, 1994) and aging (Kisic et al, 2012) may play a role. Moreover, studies over the years have established oxidative stress as a major factor that triggers cataractogenesis (Williams, 2006; Babizhaye et al, 2010) with lipid peroxidation products in the lens correlating with opacity (Marsili et al, 2004). Lipid peroxidation may be triggered by endogenous and exogenous insults such as reactive oxygen species (ROS), metal ions, ultraviolet irradiations and drugs (Kisic et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the effect of <i>Spathodea campanulata</i> flower bud exudate on cataractogenesis in rat lenses

Gbemisola¹,

Faluyi²,

Osoniyi³

2015

Afr. J. Trad. Compl. Alt. Med.

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Background: The flower bud exudates of Spathodea campanulata is commonly used as a local eye drop in Nigeria and is anecdotally claimed to improve vision. This study evaluated the anti-cataract activity of Spathodea campanulata (SPCM) flower bud exudates against cataractogenesis using rat lenses. This was done with a view to providing empirical scientific support for the use of the exudates from SPCM in the treatment and management of certain eye disorders. Materials and Methods: Fifty (50) rat lenses were used in this study, i.e. five groups of ten (10) lenses per group. Lenses were incubated in artificial aqueous humor (Normal control) with simultaneous incubation in 30 mM galactose (Untreated cataract). Co-incubation with captopril (Captopril treated cataract); 0.1 mg/ml of the exudate (Exudate treated cataract -Low dose) and 0.2 mg/ml of exudate (Exudate treated cataract-High dose) constituted the study groups. After 72 hr of incubation, lenses were observed for cataract and the preventive potential of the exudate against cataractogenesis was evaluated through the determination of the levels of anti-oxidant parameters such as total protein (TP), glutathione (GSH), malondialdehyde (MDA) and activities of superoxide dismutase (SOD) and catalase (CAT) were evaluated in the lens homogenates. Results: Photographic evaluation of the lenses showed the development of cataract in the untreated cataract group while opacification was retarded in higher dose exudate-treated and captopril treated lenses. Significant decrease in the levels of GSH and total protein, reduction in SOD and CAT activities as well as increase in MDA content were observed in cataractous lenses when compared with the normal control. SPCM displayed a doserelated anti-cataract activity. Captopril showed comparable anti-cataract potential to (0.2 mg/ml) SPCM. GSH, SOD and CAT activity in captopril treated cataract lenses increased to 75.55%, 64.08% and 72.45% of the normal control values respectively. In (0.2 mg/ml) exudate treated cataract lenses; GSH, SOD and CAT activity increased to 57.7%, 76.69% and 80.61% respectively. Conclusion:The study concluded that exudate of SPCM elicited its anti-cataract potential through its anti-oxidant activities.

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Oxidation, antioxidants and cataract formation: a literature review

Abstract: Dietary antioxidants are likely to be important in retarding cataractogenesis in older animals and in humans. Work on companion animals could provide a valuable stepping stone between rodent-based laboratory work and human interventional studies.

Cited by 79 publications

References 75 publications

Taurine Prevents Oxidative Damage of High Glucose-Induced Cataractogenesis in Isolated Rat Lenses

Taurine Prevents Oxidative Damage of High Glucose-Induced Cataractogenesis in Isolated Rat Lenses

Optimisation of gene expression analysis in Atlantic salmon lenses by refining sampling strategy and tissue storage

Evaluation of the effect of <i>Spathodea campanulata</i> flower bud exudate on cataractogenesis in rat lenses

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