As one of the greatest inventions of the 20th century, in vitro fertilization (IVF) has brought the gospel to many families. However, studies have shown that in vitro fertilization IVF and naturally conceived infants there are differences, but also the emergence of gender imbalance, the reason why? Recently, China Agricultural University, Professor Tian Jianhui study found the mystery. How is this discovery achieved and how will relevant research further affect the development of related technologies? Professor Tian Jianhui accepted the reporter's interview.
Reporter: First of all, congratulations to your research team has achieved breakthrough results. Please briefly explain the results obtained by the process.
Tian Jianhui: This study, we lasted five years. In order to assure the reliability of the experimental evidence, the sample size was increased as much as possible. In order to prove that IVF had sex imbalance in the experiment, the sample size of each time point in each group was more than 500; Methods also strive to solid, as much as possible to reduce miscarriage of justice. During the course of the study, we examined whether the gender imbalance in the IVF technique was caused by a lack of X-chromosome inactivation (XCI). We conducted a series of analyzes and experiments to address this issue. The findings were published in the recent " National Academy of Sciences "(PNAS) magazine.
Reporter: The general public will worry: Does this mean that IVF technology insecurity? Is your research finding to alert you?
Tian Jianhui: Our research is not simply to deny the IVF technology itself, nor is it to give infertile patients to give up their own children through IVF fertility. But in order to reveal the source of the existence of these risks IVF technology reasons, and to provide a path for the optimization of IVF system.
IVF technology is an effective choice of infertile people, the ultimate goal of our research is to make IVF technology safer and better serve the human.
Reporter: So, how does your research team find the connection between IVF technology and gender imbalance?
Tian Jianhui: My research team, PhD student Tan Kun and other in 2011 found that the use of in vitro fertilization techniques in the breeding of mice with gender imbalance. Further studies have shown that in vitro fertilization embryos X chromosome inactivation problem, they infer that this may be the main cause of gender imbalance. On this basis, we found that Xist and loop finger protein 12 (Rnf12) play an important role in IVF-induced X-chromosome inactivation.
Reporter: What is Xist and Ring finger protein 12 (Rnf12)?
Tian: Xist is a non-coding RNA, can be wrapped in the inactivated X chromosome, and Rnf12 is Xist upstream regulatory factors. In the IVF technique, the expression of both components in the female embryo is impaired, but not in the male, which leads to abnormal development of the embryo, resulting in gender imbalance.
Reporter: This discovery, how to optimize and improve the IVF technology?
In this study, we found that Xist and Rnf12 are the key genes of X chromosome inactivation. We used experimental method to up-regulate the expression of Rnf12. The results confirmed that Xist expression could be compensated and the gender imbalance in IVF embryos could be effectively reversed. And our method is to add retinoic acid to the embryo before implantation of the medium. Because, retinoic acid can act on the pluripotency factor, activation of Xist expression, and then correct the X chromosome inactivation, thereby avoiding the birth sex imbalance.
Therefore, we tried to improve the IVF development system by adding retinoic acid, which also provides a reference for exploring the health problems associated with in vitro fertilization.
Reporter: Your discovery, will undoubtedly bring an important way to IVF technology development thinking.
Tian Jianhui: We always believe that in vitro fertilization operation and the environment caused by the apparent cosmetic error, is the IVF embryo and the offspring of the main causes of health problems. The detection and correction of these apparent errors can effectively prevent these health problems. Of course, it needs to explore what specific cosmetic errors caused by specific problems, and then put forward specific solutions.
Reporter: Your discovery, will soon apply to clinical?
Tian Jianhui: At present, this study is only in experimental animals, found a potential mechanism, but also through the targeted improvement of IVF process of the culture system to solve this problem. But whether it applies to humans, there are still a series of problems.
First, human embryos and experimental mouse embryo development process differences, need further evidence to determine the consistency between species issues; Second, the ethical issue has been the human embryo research needs attention, in order to verify this discovery in the human body , The need for natural production of embryos, which is not allowed; Third, the clinical application, such as retinoic acid added, still need to conduct a series of risk assessment to ensure safe and reliable. At present, existing human data suggest that human IVF embryos may also be deficient in XCI. However, this hypothesis can not be confirmed by experiments at present.
Reporter: So, the next step Retinoic acid Tretinoin should be how to advance the study to bring practical effect?
Tian Jianhui: We believe that the focus of future research, the first is to reveal the normal mechanisms of early embryonic development, especially in humans. Second, we can not directly study the human IVF embryos, animal models found in the mechanism and the corresponding preventive measures can be used for clinical application of human IVF, which will be the future research needs to be addressed.
