London, July 9 : Brazilian researchers say that stem cells from human teeth seem to grow into sperm when injected into the testes of mice.
Irina Kerkis of the Butantan Institute, Sao Paulo, and her colleagues believe that the findings may some day prove helpful in curing infertile men.
During the study, the researchers injected stem cells from the dental pulp of human teeth into the testes of live mice.
They said that the cells appeared to migrate to the tubules where sperm usually mature, and differentiate into cells resembling human sperm.
The researchers, however, conceded that the approach was inefficient.
They found that some of the human cells fused with mouse cells, a problem that would have to be solved before the technique could be used therapeutically.
Given that the researchers used cells taken from baby teeth during the study, it is yet to be determined whether the process would work with teeth from adult men.
"I think we are on the right track, but we need to understand more about the mechanism," New Scientist magazine quoted Kerkis as saying.
Some other researchers are sceptical about the findings because human sperm takes several weeks to develop, while the Brazilian team's cells seemed to have matured within nine days.
Robin Lovell-Badge of the National Institute for Medical Research in London, UK, highlighted the fact that human sperm stem cells had previously failed to mature in mouse testes.
He said that it seemed unlikely that dental cells would fare better.
A presentation on the study was made at the meeting of the European Society of Human Reproduction and Embryology in Barcelona, Spain, on Wednesday.