Suryanarayana Palla, Saraswat Megha, Mrudula Tiruvalluru, Krishna T Prasanna, Krishnaswamy Kamala, Reddy G Bhanuprakash
National Institute of Nutrition (ICMR), Hyderabad, India.
Invest Ophthalmol Vis Sci. 2005 Jun;46(6):2092-9. doi: 10.1167/iovs.04-1304.
The purpose of this study was to investigate the effect of curcumin and its source, turmeric, on streptozotocin-induced diabetic cataract in rats.
Wistar-NIN rats were selected and diabetes was induced by streptozotocin (35 mg/kg body weight, intraperitoneally) and divided into four groups (group II-V). The control (group I) rats received only vehicle. Group I and II animals received an unsupplemented AIN-93 diet, and those in groups III, IV, and V received 0.002% and 0.01% curcumin and 0.5% turmeric, respectively, in an AIN-93 diet for a period of 8 weeks. Cataract progression due to hyperglycemia was monitored by slit lamp biomicroscope and classified into four stages. At the end of 8 weeks, the animals were killed and the biochemical pathways involved in the pathogenesis of cataract such as oxidative stress, polyol pathway, alterations in protein content and crystallin profile in the lens were investigated, to understand the possible mechanism of action of curcumin and turmeric. Blood glucose and insulin levels were also determined.
Although, both curcumin and turmeric did not prevent streptozotocin-induced hyperglycemia, as assessed by blood glucose and insulin levels, slit lamp microscope observations indicated that these supplements delayed the progression and maturation of cataract. The present studies suggest that curcumin and turmeric treatment appear to have countered the hyperglycemia-induced oxidative stress, because there was a reversal of changes with respect to lipid peroxidation, reduced glutathione, protein carbonyl content and activities of antioxidant enzymes in a significant manner. Also, treatment with turmeric or curcumin appears to have minimized osmotic stress, as assessed by polyol pathway enzymes. Most important, aggregation and insolubilization of lens proteins due to hyperglycemia was prevented by turmeric and curcumin. Turmeric was more effective than its corresponding levels of curcumin.
The results indicate that turmeric and curcumin are effective against the development of diabetic cataract in rats. Further, these results imply that ingredients in the study's dietary sources, such as turmeric, may be explored for anticataractogenic agents that prevent or delay the development of cataract.
本研究旨在探讨姜黄素及其来源姜黄对链脲佐菌素诱导的大鼠糖尿病性白内障的影响。
选用Wistar-NIN大鼠，通过腹腔注射链脲佐菌素（35mg/kg体重）诱导糖尿病，并分为四组（II-V组）。对照组（I组）大鼠仅接受赋形剂。I组和II组动物接受未添加其他成分的AIN-93饮食，III组、IV组和V组动物分别在AIN-93饮食中添加0.002%和0.01%的姜黄素以及0.5%的姜黄，持续8周。通过裂隙灯生物显微镜监测高血糖导致的白内障进展情况，并分为四个阶段。在8周结束时，处死动物，研究白内障发病机制中涉及的生化途径，如氧化应激、多元醇途径、晶状体中蛋白质含量和晶状体蛋白谱的变化，以了解姜黄素和姜黄可能的作用机制。同时测定血糖和胰岛素水平。
尽管通过血糖和胰岛素水平评估，姜黄素和姜黄均未预防链脲佐菌素诱导的高血糖，但裂隙灯显微镜观察表明，这些补充剂延缓了白内障的进展和成熟。目前的研究表明，姜黄素和姜黄治疗似乎对抗了高血糖诱导的氧化应激，因为脂质过氧化、还原型谷胱甘肽、蛋白质羰基含量和抗氧化酶活性的变化有显著逆转。此外，通过多元醇途径酶评估，姜黄或姜黄素治疗似乎使渗透应激最小化。最重要的是，姜黄和姜黄素预防了高血糖导致的晶状体蛋白聚集和不溶性。姜黄比相应水平的姜黄素更有效。
结果表明，姜黄和姜黄素对大鼠糖尿病性白内障的发展有效。此外，这些结果意味着可以探索本研究饮食来源中的成分，如姜黄，以寻找预防或延缓白内障发展的抗白内障药物。
