8：一 t、*女研究人员发现肌肉老化原因。…，；一^。～。有望带来抗肌肉衰老新疗法。“Ⅳ．“㈠*j一+**#。；一j|“”：2人在衰老的过程中．肌肉的力量会越来越小，对于肌肉损伤的修复能力也会不断下降。最近．一国际研究小组发现，一种名为FGF21构蛋白在这一过程中扮演着重要角色．而通过小鼠研究表明．利用常规药物可以阻止这一进程。这一研究发现对于了解肌肉老化的进程十分重要．且使得未来开发可使肌肉“返老还童“的新疗法成为可能。该研究小组由英国伦敦国王学院，美国哈佛大学及麻省总医院的研究人员组成．他们发表在最近一期《自然》杂志上的论文称．在人体内的每一块肌肉组织中，都有一些处于休眠状态的干细胞．这些干细胞会在肌肉受损伤时被激活，分裂成数百个新的肌肉纤维来修复受损肌肉。在修复过程结束时，会有一些细胞重新补充到休眠状态的干细胞群中．以保持未来对肌肉的持续修复能力。研究人员进行了一项针对衰老期的小鼠的研究。他们发现．随着年龄增长．小鼠体内处于休眠状态的干细胞会逐渐减少．这或许解释了为什么随着年龄的增长．肌肉的修复和再生能力会逐渐下降。通过对小鼠老化肌肉进行扫描发现，在老化的肌肉Maki ng old muscles good as newAn inte rnationaI team of scientists have identified for the first time a key factor responsible for declining muscle repair during ageing．The researchers fromKing’SCollegeLondon，HarvardUniversity andMassachUSettsGene ralHospital also discovered how to halt the age‘ing process in mice by administering a common a protein inhibiting drug．The study looked at stem ceIIs foUnd inside muscle and responsible for repairing injury to find out why the ability of muscles to regenerate declines with age．A dormant reservoir of stem cells is present inside every muscle， ready to be activated by exercise and injury to repair any damage．When needed，these cells divide into hundreds of new muscle fibres that repair the muscle．At the end of the repairing process some of these cells also replenish the pooI of dormant stem cellsSO that the muscle retains the ability to repair over and over again．The researchers carried out a study on old mice and found the number of dormant stem ce||s present in the pooI reduces with age，which could explain the decline in the muscle's ability to repair and regenerate as it gets older．When theseOld mUSCIes were scrutinised，highIevels ofFGF2，a protein that has the ability to stimulate cells to divide．While encouraging stem cells to divide and repair muscle iS a3中．～种名为FGF2的蛋白水平极高。这种蛋白具有刺激细胞分裂的能力，即使在不需要的时候，它们也会唤醒休眠干细胞。而对休眠干细胞的持续激活．则意味着干细胞群内细胞数量会逐渐减少．而当肌肉组织真正需要干细胞来修复的时候．却无法作出正常的反应。进一步研究表明．通过一种常见的FGF2抑制药物．可以抑制FGF2蛋白，阻止干细胞被不必要的激活，进而抑制小鼠肌肉组织内干细胞数量的下降。研究人员表示，现在还不知道为何FGF2蛋白水平会随 nOrmal and cruciaI process．they found thatFGF2 could also awaken the dormant pool of stem cells even when they were not needed which over time meant the pool was depleted．This meant that when the muscle really needed stem cells to repair itself there were insufficient to aIlOW the muscle to respond properly．Following this finding，the resea rchers were successfu|in inhibitingFGF2 in old muscles in order to prevent the stem cell pool from being kick-started into action unnecessarily by administering a commonFGF2 inhibitor drug．D rAIbe rtBasson，SeniorLectu rer at theKing’SCollegeLondonDenta|lnstitute．said：国际科技信息着年龄的增长而增加．并在不需要的时候激活干细胞．这需要进行更多的研究。而下一步工作则是要分析人体老化肌肉的状况，看人体肌肉纤维中干细胞的损耗是否与小鼠具有同样的机制。伦敦国王学院的艾伯特巴松博士表示．目前来说．预防或逆转老年人的肌肉衰老是一个遥远的目标．但新研究首次揭示了老年人肌肉老化的过程，这一结果令人兴奋。这一发现使得科学家将来有可能找到一种使肌肉“返老还童“的疗法．而一旦做到这一点．则意味着老年人可以更加自由、独立地生活。。Preventing or reversing muscle wasting in old age in humans is still a way off,but this study has for the n瞰time revealed a process which could be responsible for age—related muscle wasting，which is extremely exciting．KieranJones，co-author ofthe study fromKing’S．added：。We do not yet know how or why levels of the proteinFGF2 increase with age， triggering stem cells to be activated when they are not needed．This is something that needs to be explored．。The next step is to analyse old muscle in humans to see if the same mechanismCOUId be responsible for stem cell depletion in human muscle fibres,Ieading to loss of mass and wastagej㈣