孕期营养不良,实验小鼠 z-bo 2020-08-18 611

　　Pregnancy When a pregnant woman is malnourished, her baby is prone to obesity and type 2 diabetes, which is an "epigenetic" effect. A recent new study confirms that the "memory" of malnutrition during pregnancy is passed on to the next generation through the sperm of male offspring, thereby increasing the risk of illness for grandchildren. In other words, the diet of your pregnant grandmother will determine your health. How do epigenetic effects pass from one generation to the next? It is difficult to explain why the offspring inherit the environment of their parents. The most reasonable explanation is the mechanism of methylation, in which methyl molecules attach to DNA and control gene conversion. Researchers have shown that environmentally induced methylation changes occur only in specific regions of genes, but, unexpectedly, these specific methylation patterns are still uncertain.

　　Researchers tried to use mice to model the effects of malnutrition during pregnancy on the offspring and find out how the offspring affect the infection. As expected, male mice born from malnourished pregnant mice are relatively small and develop diabetes after being fed a normal diet and water. Surprisingly, even if the offspring of these male mice are not malnourished during pregnancy, the offspring of these male mice seem to be very young and are prone to diabetes in adulthood. Researchers say that when their mothers lose food, their babies will follow prescribed procedures and quickly cope with malnutrition. When there is a sudden increase in food, the body cannot cope with it and causes metabolic diseases such as diabetes. Understanding the mechanism of this adaptive change helps humans understand the causes of obesity and type 2 diabetes. To understand how this effect is inherited, the researchers analyzed sperm methylation patterns shortly before the individual developed symptoms of diabetes. It was found that compared with the control group, the DNA from the test mice had a lower degree of methylation in 111 relevant regions. These regions mainly gather in the non-coding regions of DNA, and the non-coding regions of DNA are related to the regulation of mouse genes. This shows that in grandchildren, these genes that are close to methylation are not functioning properly, and the offspring inherited the "memory" of malnutrition from their grandmother. Studies on the DNA of grandchildren show that the changes in methylation have disappeared, that is, the memory of malnutrition is eliminated at the DNA level, and this "memory" is not passed on to the offspring through the inheritance of methylation.

　　Traditional thinking suggests that these methylation patterns may persist in offspring. This makes us optimistic that the effects of social obesity and diabetes can be reversed, or even completely reversed. Now, researchers are looking for whether epigenetic effects actually affect grandchildren and offspring. If this is the case, in fact, the impact of malnutrition by the grandmother will not be great.