生物谷報道：肢體如何再生,、脊髓如何修復(fù),？其機(jī)制正在逐漸明朗化。Forsyth研究所研究人員利用非洲蟾蜍屬蝌蚪,，研究了其尾芽再生過程中細(xì)胞數(shù)量控制的動態(tài)變化,。結(jié)果表明，尾芽再生除須有大量組織增生外,，早期還必須有凋亡發(fā)生,。如果在24小時內(nèi)抑制凋亡,，再生過程將不能開始，神經(jīng)軸生長也發(fā)生異常,，而后期抑制凋亡無效,，提示再生過程中某些細(xì)胞的程序性死亡發(fā)生在極早期。
      研究小組由Forsyth再生及發(fā)育生物學(xué)中心負(fù)責(zé)人Michael Levin博士帶頭,，研究成果將發(fā)表于《發(fā)育生物學(xué)》2007年1月1日刊,。第一作者Ai-Sun Tseng博士說：“我們非常驚訝地發(fā)現(xiàn)，有些細(xì)胞必須被清除才能使再生開始,。我們設(shè)想這一過程將來會有一天用于再生療法,，這很令人振奮。
       此研究也許會有助于明確再生療法將如何應(yīng)用于人體,，如那些因遺傳性疾病,、出生缺陷、癌癥,、退行性病變,、事故、老化以及臟器功能衰竭等丟失,、損傷或失去功能的組織,。Levin小組在今后的實(shí)驗(yàn)中，將明確這些必須死亡的細(xì)胞群,，并探討細(xì)胞控制生長的信號,。

原文出處：

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.

作者簡介：

Levin Lab web page