During 1994, researchers from the College of Veterinary Medicine of the University of Pennsylvania developed a method to transplant spermatogonial stem cells into mice. From 65438 to 0996, the researchers implanted frozen spermatogonial stem cells from healthy male mice into infertile male mice, which successfully produced sperm. However, in the following years, the research on artificial sperm made little progress.
Until the beginning of 2003, a Japanese research team announced that they had successfully turned embryonic stem cells of experimental mice into sperm cells.
In 2004, a research team led by George Daley of Harvard Medical School reported that they used embryonic stem cells of male mice to cultivate sperm cells and injected them into eggs. This is also the first report that artificial sperm is used for egg fertilization. In the same year, scientists in Singapore cultivated fish spermatogonial stem cells, from which live mature fish sperm were cultivated.
On April 22, 2004, the authoritative scientific magazine Nature published shocking news: Japanese and Korean scientists used the unfertilized mature eggs of two female mice to recombine and cultivate a parthenogenetic mouse without a "father" and named it "Huijiye". Female "Artificial Sperm" Technology
Only men can produce sperm, but scientists at Newcastle University plan to extract stem cells from female bone marrow and cultivate female "artificial sperm".
British scientists have applied for experiments. Once approved, British scientists will cultivate mature female "artificial sperm" within five years. Starting from 20 13, women can reproduce their offspring without male participation at all.
Scientists say that "artificial sperm" technology will bring good news to many infertile patients. However, this groundbreaking technology has also caused fierce ethical controversy, because it can make women "parthenogenesis" completely independent of men.
Mature female "artificial sperm" will be able to fertilize eggs and give birth in vitro. This means that, in theory, women can have children independently of men. However, Professor Naje Nya said that, first of all, he had no intention of fertilizing female "artificial sperm" with human eggs. If scientists want to carry out such artificial insemination experiments, they must first obtain the approval of the British Human Insemination and Embryology Authority.
However, Professor Naje Nya said that if they can really cultivate mature "artificial sperm" from female bone marrow cells in the future and use them to breed offspring, then these "artificial sperm" can only give birth to daughters, because the "artificial sperm" cultivated from female cells will lack the Y chromosome necessary for giving birth to boys.
Scientists have also observed that only embryonic stem cells with XY chromosome can finally cultivate artificial sperm, while stem cells with XX chromosome with female characteristics can form early spermatogonial stem cells, but they can never pass the test of meiosis i ya.
As we know, the difference between men and women is that men carry XY chromosomes, while women carry XX chromosomes. On the other hand, sperm cells have only half the number of chromosomes, half are Y chromosomes and half are X chromosomes. In the laboratory environment, XX chromosome stem cells with female characteristics can also form early spermatogonial stem cells.
Theoretically, such spermatogonial stem cells can also form sperm cells containing X chromosome through meiosis. More directly, artificial sperm can be cultivated from female somatic cells by biotechnology. Of course, this artificial sperm can only produce female offspring after combining with eggs.
However, in the current experiment, the reason is not clear.
Male "Artificial Sperm" Technology
It is reported that Karim Naje, a professor at Newcastle University in England, and his colleagues have mastered the technology of cultivating "artificial sperm" from male bone marrow cells. In the experiment, Professor Naje Nya's research team extracted some bone marrow tissues from male volunteers and isolated stem cells from them, and then scientists cultured these stem cells into spermatogonia. For most men, the spermatogonia in their bodies can eventually develop naturally into mature sperm.
Spermatogonial cells cultured in the laboratory have not yet developed into sperm, but the results of this study make scientists very excited, because they believe that it will take them at most three or five years to make the spermatogonial cells in the laboratory develop into mature sperm. Scientists first extract stem cells from male mouse blastocysts, which can be said to be the mother of cells and can divide into various tissues in the organism. After a period of culture, scientists labeled some early sperm cells (spermatogonial stem cells) in stem cells, and then isolated the labeled spermatogonial stem cells and cultured them for a period of time. Finally, spermatogonial stem cells combine with mouse eggs to form fertilized eggs. When the fertilized egg was implanted into the uterus of the surrogate mother, a new mouse was born.