What is the secret to aging more slowly and living longer Not antioxidants, apparently1. Many people believe that free radicals3, the sometimes-toxic molecules4 produced by our bodies as we process oxygen, are the culprit behind aging. Yet a number of studies in recent years have produced evidence that the opposite may be true.Now, researchers at McGill University have taken this finding a step further by showing how free radicals promote longevity5 in an experimental model organism, the roundworm C. elegans. Surprisingly, the team discovered that free radicals -- also known as oxidants（氧化剂） -- act on a molecular6 mechanism7 that, in other circumstances, tells a cell to kill itself.Programmed cell death, or apoptosis（细胞死亡）, is a process by which damaged cells commit suicide in a variety of situations: to avoid becoming cancerous, to avoid inducing auto-immune disease, or to kill off viruses that have invaded the cell. The main molecular mechanism by which this happens is well conserved8 in all animals, but was first discovered in C. elegans -- a discovery that resulted in a Nobel Prize.The McGill researchers found that this same mechanism, when stimulated10 in the right way by free radicals, actually reinforces the cells defenses and increases its lifespan. Their findings are reported in a study published online May 8 in the journal Cell.People believe that free radicals are damaging and cause aging, but the so-called free radical2 theory of aging is incorrect, says Siegfried Hekimi, a professor in McGills Department of Biology and senior author of the study. We have turned this theory on its head by proving that free radical production increases during aging because free radicals actually combat -- not cause -- aging. In fact, in our model organism we can elevate free radical generation and thus induce a substantially longer life.The findings have important implications. Showing the actual molecular mechanisms11 by which free radicals can have a pro-longevity effect provides strong new evidence of their beneficial effects as signaling molecules, Hekimi says. It also means that apoptosis signaling can be used to stimulate9 mechanisms that slow down aging. Since the mechanism of apoptosis has been extensively studied in people, because of its medical importance in immunity12 and in cancer, a lot of pharmacological tools already exist to manipulate apoptotic signaling. But that doesnt mean it will be easy.Stimulating13 pro-longevity apoptotic signaling could be particularly important in neurodegenerative diseases, says Hekimi. In the brain the apoptotic signaling might be particularly tilted14 toward increasing the stress resistance of damaged cells rather than killing15 them, explains Hekimi. Thats because it is harder to replace dead neurons than other kinds of cells, partly because of the complexity16 of the connections between neurons.
点击收听单词发音
1 apparently adv.显然地；表面上，好像 参考例句： An apparently blind alley leads suddenly into an open space.山穷水尽，豁然开朗。 He was apparently much surprised at the news.他对那个消息显然感到十分惊异。
相关文章推荐
