幹細胞論壇

美國研究人員１０日報告說，他們以腿部肌肉受傷的年輕實驗鼠為研究對象發現，植入肌肉幹細胞可以使實驗鼠肌肉恢復得比受傷前更強大，還可幫助實驗鼠抵禦因衰老而導致的肌肉萎縮。

研究人員植入的肌肉幹細胞來自健康的年輕實驗鼠。植入手術後，受傷實驗鼠腿部肌肉不僅在幾天內得以恢復，而且這一部位的肌肉質量增大為受傷前的170%。研究人員最初認為，這可能是暫時現象，但他們最終發現，實驗鼠肌肉終其一生（約為兩年）都保持這一水平，而且與普通老鼠相比，它們的肌肉更能夠抵禦老化過程，肌肉力量和質量能持續保持。

研究人員提醒說，他們在實驗中發現，將肌肉幹細胞植入健康實驗鼠不能起到同樣效果。他們認為，這表明幹細胞被植入的環境非常重要，不同環境下，幹細胞反應的方式也不一樣。

參與研究的科羅拉多大學布拉德利‧奧爾溫教授表示，如果這一成果能夠應用於人類，肌肉萎縮症等疾病就有望找到新療法。研究人員目前已著手進行將人類或大型動物的幹細胞植入實驗鼠的實驗，以驗證是否能收到同樣效果。

相關研究成果１０日發表在美國《科學‧轉化醫學》雜誌上。

Stem Cells could boost muscle

If the same applies to humans, the findings could lead to new treatments for diseases that cause muscles to deteriorate, such as muscular dystrophy.

It may even help people resist the gradual erosion of muscle strength that comes with age, Bradley Olwin, of the University of Colorado at Boulder, and colleagues reported in the journal Science Translational Medicine.

"This was a very exciting and unexpected result," Olwin, who worked on the study, said in a statement.

"We found that the transplanted stem cells are permanently altered and reduce the aging of the transplanted muscle, maintaining strength and mass."

Olwin's team experimented on young mice with leg injuries, injecting them with muscle stem cells taken from young donor mice.

Stem cells are unique in that they can constantly renew themselves, and form the basis of other specialized cells.

These cells not only repaired the injury, but they caused the treated muscle to increase in size by 170 percent.

Olwin's team had thought the changes would be temporary, but they lasted through the lifetime of the mice, which was about two years.

"When the muscles were examined two years later, we found the procedure permanently changed the transplanted cells, making them resistant to the aging process in the muscle," Olwin said in a statement.

Olwin and colleagues said when they injected the cells into a healthy leg, they did not get the same effect, suggesting there is something important about injecting the cells into an injured muscle that triggers growth.

"The environment that the stem cells are injected into is very important, because when it tells the cells there is an injury, they respond in a unique way," he said.

The team hopes eventually to find drugs or combinations of drugs that mimic the behavior of transplanted cells," Olwin said.

The findings are encouraging for human research, but Olwin cautions that putting stem cells from young mice into other young mice is not the same thing as making old muscles young again.

And the study is in mice, not people.