莱菔硫烷(花菜)对健康有益，能够对抗自由基！

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Study finds that broccoli may help boost the aging immune system

Published in this week's online edition of the Journal of Allergy and Clinical Immunology, the study findings show that sulforaphane, a chemical in broccoli, switches on a set of antioxidant genes and enzymes in specific immune cells, which then combat the injurious effects of molecules known as free radicals that can damage cells and lead to disease.

Free radicals are byproducts of normal processes, such as the metabolic conversion of food into energy, and can also enter the body through small particles present in polluted air. A supercharged form of oxygen, these molecules can cause oxidative tissue damage, leading to disease — for example, triggering the inflammation process that causes clogged arteries. Oxidative damage to body tissues and organs is thought to be one of the major causes of aging.

\"The mysteries of aging have always intrigued man,\" said Dr. Andre Nel, the study's principal investigator and chief of nanomedicine at the David Geffen School of Medicine at UCLA. \"While we have known for some time that free radicals are important in aging, most of the past attention has focused on the mechanisms that produce free radicals rather than addressing the pathways used by the body to suppress their production.\"

A dynamic equilibrium exists in the body between the mechanisms that lead to increased free radical production and those antioxidant pathways that help combat free radicals.

\"Our study contributes to the growing understanding of the importance of these antioxidant defense pathways that the body uses to fight free radicals,\" said Nel, a practicing clinical allergist and immunologist at the Geffen School. \"Insight into these processes points to ways in which we may be able to alleviate the effects of aging.\"

The delicate balance between pro-oxidant and antioxidant forces in the body could determine the outcome of many disease processes that are associated with aging, including cardiovascular disease, degenerative joint diseases and diabetes, as well as the decline in efficiency of the immune system's ability to protect against infectious agents.

\"As we age, the ability of the immune system to fight disease and infections and protect against cancer wears down as a result of the impact of oxygen radicals on the immune system,\" Nel said.

According to the UCLA study, the ability of aged tissues to reinvigorate their antioxidant defense can play an important role in reversing much of the negative impact of free radicals on the immune system. However, until this current study, the extent to which antioxidant defense can impact the aging process in the immune system was not properly understood.

\"Our defense against oxidative stress damage may determine at what rate we age, how it will manifest and how to interfere in those processes,\" Nel said. \"In particular, our study shows that a chemical present in broccoli is capable of stimulating a wide range of antioxidant defense pathways and may be able to interfere with the age-related decline in immune function.\"

The UCLA team not only found that the direct administration of sulforaphane in broccoli reversed the decline in cellular immune function in old mice, but they witnessed similar results when they took individual immune cells from old mice, treated those cells with the chemical outside the body and then placed the treated cells back into a recipient animal.

In particular, the scientists discovered that dendritic cells, which introduce infectious agents and foreign substances to the immune system, were particularly effective in restoring immune function in aged animals when treated with sulforaphane.

\"We found that treating older mice with sulforaphane increased the immune response to the level of younger mice,\" said Hyon-Jeen Kim, first author and research scientist at the Geffen School.

To investigate how the chemical in broccoli increased the immune system's response, the UCLA group confirmed that sulforaphane interacts with a protein called Nrf2, which serves as a master regulator of the body's overall antioxidant response and is capable of switching on hundreds of antioxidant and rejuvenating genes and enzymes.

Nel said that the chemistry leading to activation of this gene-regulation pathway could be a platform for drug discovery and vaccine development to boost the decline of immune function in elderly people.

\"This is a radical new way of thinking in how to increase the immune function of elderly people to possibly protect against viral infections and cancer,\" Nel said. \"We may have uncovered a new mechanism by which to boost vaccine responses by using a nutrient chemical to impact oxidant stress pathways in the immune system.\"

Kim said that although there is a decline in Nrf2 activity with aging, this pathway remains accessible to chemicals like sulforaphane that are capable of restoring some of the ravages of aging by boosting antioxidant pathways.

The next step is further study to see how these findings would translate to humans.

\"Dietary antioxidants have been shown to have important effects on immune function, and with further study, we may be adding broccoli and other cruciferous vegetables to that list,\" Nel said.

For now, Nel suggests including these vegetables as part of a healthy diet.

Nel said that these findings offer a window into how the immune system ages.

\"We may find that combating free radicals is only part of the answer. It may prove to be a more multifaceted process and interplay between pro- and antioxidant forces,\" he said.

The study was funded by the National Institute on Aging, the UCLA Claude D. Pepper Older Adults Independence Center, and the National Institute of Allergy and Infectious Diseases.

Other study authors included Berenice Barajas and Dr. Meiying Wang.

　　　这个星期变态反应与临床免疫学期刊网络版表明：莱菔硫烷，花茎甘蓝里的一种化学物质，掌握特异性免疫细胞中的一套抗氧化基因和酶的开关，然后清除有害作用的分子-可能损坏细胞和导致疾病自由基。自由基是新陈代谢的副产物，例如食物的新陈代谢转换为能量，并且可能通过当前被污染的空气里的小颗粒进入身体。自由基是氧的超负荷形式，可能造成组织氧化损伤，从而导致疾病（触发炎症反应导致动脉堵塞）。对身体组织和器官的氧化损伤认为是衰老的一个主要原因。
　　　主要研究者和加州大学洛杉矶分校David Geffen 医学院研究纳米医药学的Andre Nel博士说：衰老的奥秘总是能吸引人，我们知道自由基是影响衰老的重要因素有一段时间了，过去大多数研究集中于自由基的产生而不是寻址于身体用于抑制自由基产生的通路。身体中存在促氧化剂和抗氧化的动态平衡。这种奇妙平衡能决定许多与衰老有关的疾病-心血管疾病, 退变性关节病和糖尿病等的结果, 并且使免疫系统对抗感染的效果下降。当我们变老时，由于氧自由基对免疫系统的影响，导致系统免疫防御和免疫监视能力下降。研究不仅发现花茎甘蓝里的莱菔硫烷直接给药逆转了老龄大鼠细胞的免疫功能下降；而且当他们采取了老龄大鼠单个的免疫细胞，用化学物质处理那些在体外的细胞和然后把处理过的细胞植回到一个受体动物，并且证实了类似的结果。特别地，科学家发现：当给予老龄大鼠莱菔硫烷时，其将病原微生物和异物的信息传递给免疫系统的树突状细胞，免疫功能的恢复十分显著，并且其下一代的免疫应答增强。花茎甘蓝里的化学物质怎样加强免疫系统的应答?加州大学洛杉矶分校研究小组证实：莱菔硫烷与身体的全部抗氧化反应一个主要管理者和接通上百个抗氧化剂和使基因和酶复兴的Nrf2蛋白相互作用。导致这条基因调节通路的活化作用的化学物质将成为发展降低老年人免疫功能衰落的药物和疫苗的一个平台。这是怎样增加老年人的免疫功能保护免受病毒传染和癌症的根本新想法，也许揭露了通过使用一种营养化学物质影响免疫系统的氧化剂应激通路促进疫苗应答的新机制。并且加强了身体利用抗氧化防御通路与自由基战斗的重要性的理解，对这些过程的观察指引我们缓和衰老的作用。我们的防御抗氧化应激损伤也许将确定什么使我们衰老，它是怎么表达和干预在那些过程。研究特别表明，当前在花茎甘蓝里化学物质能刺激大部分抗氧化防御通路，也许能干涉与衰老相关的免疫功能的下降。\"
　　　虽然随着衰老，Nrf2 蛋白活动下降。这条通路仍然容易接近莱菔硫烷等化学制品通过促进抗氧化通路修复衰老带来的一些破坏。下一步是继续研究这些结果如何在人身上发挥作用。食用抗氧剂显示对免疫功能有重要的作用，也许会增加花茎甘蓝和其它十字花科的蔬菜。Nel建议将这些蔬菜作为健康饮食的一部分。也许我们只发现与自由基交战只是答案的一部分，它也许被证明是一个多方面的过程并且在促进和抗氧化之间互相影响。研究资金由国立老年病研究院，加州大学洛杉矶分校Claude D. Pepper 老年人独立中心，和国立变态反应和传染病研究院资助。其它研究作者包括Berenice Barajas and Wang Meiying博士。