Abstract | PURPOSE: A decline in the chaperone-like activity of eye lens alpha-crystallin in diabetic conditions has been reported. In this study, we investigated whether curcumin, a dietary antioxidant, can manipulate the chaperone-like activity of alpha-crystallin in diabetic rat lens. METHODS: A group of rats received ip injection of streptozotocin (STZ; 35 mg/kg body weight in buffer) to induce hyperglycemia, while another group of rats received only buffer as vehicle and served as control. STZ-treated rats were assigned to 3 groups and fed either no curcumin or 0.002% or 0.01% curcumin, respectively. Cataract progression due to hyperglycemia was monitored with a slit lamp biomicroscope. At the end of 8 weeks animals were sacrificed and lenses were collected. alphaH- and alphaL- crystallins from a set of pooled lenses in each group were isolated by gel filtration. Chaperone activity, hydrophobicity, and secondary and tertiary structure of alphaH- and alphaL- crystallins were assessed by light scattering/spectroscopic methods. RESULTS: A decrease in chaperone-like activity of alphaH- and alphaL- crystallins was observed in STZ-treated diabetic rats. The declined chaperone-like activity due to hyperglycemia was associated with reduced hydrophobicity and altered secondary and tertiary structure of alphaH- and alphaL- crystallins. Interestingly, alphaH- and alphaL- crystallins isolated from curcumin fed diabetic rat lenses had shown improved chaperone-like activity as compared to alphaH- and alphaL- crystallins from untreated diabetic rat lens. Feeding of curcumin prevented the alterations in hydrophobicity and structural changes due to STZ-induced hyperglycemia. Modulation of functional and structural properties by curcumin was found to be greater with the alphaL- crystallin than alphaH- crystallin. Loss of chaperone activity of alpha-crystallin, particularly alphaL- crystallin, in diabetic rat lens could be attributed at least partly to increased oxidative stress. Being an antioxidant, curcumin feeding has prevented the loss of alpha-crystallin chaperone activity and delayed the progression and maturation of diabetic cataract. CONCLUSIONS: We demonstrate that curcumin, at the levels close to dietary consumption, prevented the loss of chaperone-like activity of alpha-crystallin vis-a-vis cataractogenesis due to diabetes in rat lens.
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Authors | P Anil Kumar, P Suryanarayana, P Yadagiri Reddy, G Bhanuprakash Reddy |
Journal | Molecular vision
(Mol Vis)
Vol. 11
Pg. 561-8
(Jul 26 2005)
ISSN: 1090-0535 [Electronic] United States |
PMID | 16088325
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- Antioxidants
- Blood Glucose
- Molecular Chaperones
- alpha-Crystallins
- Curcumin
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Topics |
- Animals
- Antioxidants
(administration & dosage)
- Blood Glucose
(analysis)
- Body Weight
- Cataract
(metabolism, physiopathology)
- Chromatography, Gel
- Circular Dichroism
- Curcumin
(administration & dosage)
- Diabetes Mellitus, Experimental
(metabolism)
- Diet
- Hyperglycemia
(metabolism, physiopathology)
- Lens, Crystalline
(metabolism)
- Male
- Molecular Chaperones
(metabolism)
- Rats
- Spectrometry, Fluorescence
- alpha-Crystallins
(metabolism)
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