生物谷报道：肢体如何再生、脊髓如何修复？其机制正在逐渐明朗化。Forsyth研究所研究人员利用非洲蟾蜍属蝌蚪，研究了其尾芽再生过程中细胞数量控制的动态变化。结果表明，尾芽再生除须有大量组织增生外，早期还必须有凋亡发生。如果在24小时内抑制凋亡，再生过程将不能开始，神经轴生长也发生异常，而后期抑制凋亡无效，提示再生过程中某些细胞的程序性死亡发生在极早期。
研究小组由Forsyth再生及发育生物学中心负责人Michael Levin博士带头，研究成果将发表于《发育生物学》2007年1月1日刊。第一作者Ai-Sun Tseng博士说：“我们非常惊讶地发现，有些细胞必须被清除才能使再生开始。我们设想这一过程将来会有一天用于再生疗法，这很令人振奋。
此研究也许会有助于明确再生疗法将如何应用于人体，如那些因遗传性疾病、出生缺陷、癌症、退行性病变、事故、老化以及脏器功能衰竭等丢失、损伤或失去功能的组织。Levin小组在今后的实验中，将明确这些必须死亡的细胞群，并探讨细胞控制生长的信号。
原文出处：
http://www.medicalnewstoday.com/medicalnews.php?newsid=58919
Forsyth Scientists Discover Early Key To Regeneration
Science may be one step closer to understanding how a limb can be grown or a spinal cord can be repaired. Scientists at The Forsyth Institute have discovered that some cells have to die for regeneration to occur. This research may provide insight into mechanisms necessary for therapeutic regeneration in humans, potentially addressing tissues that are lost, damaged or non- functional as a result of genetic syndromes, birth defects, cancer, degenerative diseases, accidents, aging and organ failure. Through studies of the frog (Xenopus) tadpole, the Forsyth team examined the cellular underpinnings of regeneration.
The Xenopus tadpole is an ideal model for studying regeneration because it is able to re-grow a fully functioning tail and all of its components, including muscle, vasculature, skin, and spinal cord. The Forsyth scientists studied the role that apoptosis, a process of programmed cell death in multi-cellular organisms, plays in regeneration. The research team, led by Michael Levin, Ph.D., Director of the Forsyth Center for Regenerative and Developmental Biology, found that apoptosis has a novel role in development and a critical role in regeneration. According to Dr. Levin, "Simply put, some cells have to die for regeneration to happen."
The findings will be published in the January 1, 2007 issue of Developmental Biology (v301i1). "We were surprised to see that some cells need to be removed for regeneration to proceed," said Ai-Sun Tseng, Ph.D. the paper's first author. "It is exciting to think that someday this process could be managed to allow medically therapeutic regeneration."
Summary of Study
In the context of efforts to understand biophysical controls of regenerative processes, The Forsyth Center for Regenerative and Developmental Biology investigated the dynamics of cell number control in the regenerating tail bud. Previous research in the field has shown that one mechanism by which cell number is controlled is by programmed cell death, which has been shown to be involved in sculpting of growing tissue in a number of developmental systems including heart, limb and craniofacial patterning. This study shows that despite the massive tissue proliferation required to build the tail, an early apoptotic event is required for regeneration. Normal regeneration of the tail includes a small focus of apoptotic cells; when apoptosis is inhibited during the first 24 hours, regeneration cannot proceed and the growth of nerve axons becomes abnormal. Later inhibition of apoptosis has no effect, suggesting that the programmed death of a specific cellular component is a very early step in the regeneration program. One possible model is that tissues normally contain a population of cells whose purpose is to prevent massive growth in the region surrounding them. Future work by the Levin group will identify the cells that must die, in order to try to understand the signals that cells utilize for growth control.
作者简介：
Levin Lab web page
