Image: Fang Bing Huang Zai | Written by: Ah Jing | Editor-in-Charge: Suzuran
Hello everyone, the new issue of "No. 11 Lab" is meeting you again, the theme of this issue is "Sexual and Reproductive Health", this time we will bring you some interesting research, come and see it together~
In this issue you will see:
The number of male rice greens is getting smaller and smaller? It turned out to be its pot!
Parthenogenesis achieved? No man can have children!
The secret of female orgasm, told clearly by 12 rabbits?
Extending the optimal age for childbearing? Maybe it can become a reality!
The number of male rice greens is getting smaller and smaller?
It turned out to be its pot!
In the past few decades, the number of rice green seeds in men around the world has declined, and the quality has become worse and worse, and poor lifestyles and harsh living environments have played an important role in it, such as staying up late, overeating, consuming a lot of tobacco, alcohol and coffee, sexual chaos and environmental pollution.
Speaking of this, Ah Jing remembered the "Mi Qingzi Competition" held by the Shanghai Human Rice Qingzi Library at the end of last year, and they invited Shanghai university students to participate in the free physical examination and conduct the "Rice Qingzi Competition", which was evaluated according to the concentration, vitality, amount of rice Green liquid, deformity rate and other indicators of Mi Qingzi.
However, this competition failed to select the strongest comprehensive player, because the concentration of the athletes with strong vitality of Mi Qingzi did not reach the standard, and the vitality of the strong concentration of the players did not meet the standard, and the sky was purring, to know that this is a group of male college students of about 20 years old, which can be called the real sense of "high-quality men" in the human group, so the quality of contemporary male Mi Qingzi can be seen.
In order to explore the specific causes of this problem, countless scientists have conducted a lot of research, and a paper released last year focused on "air pollution" and made the latest progress.
The study, titled "PM2.5 Exposure of Mice during Spermatogenesis: A Role of Inhibitor jB Kinase 2 in Pro-Opiomelanocortin Neurons," was published in Environmental Health by a Chinese research team from the University of Maryland School of Medicine, Nantong University, and Zhengzhou University Perspectives" on .
▲Image source: References[1]
According to known studies, miyanogenesis is complexly regulated by the hypothalamic-pituitary-gonadal (HPG) axis, inhibition of the HPG axis leads to a decrease in migranoid occurrence, and in previous epidemiological studies, almost all published animal model studies have shown that air pollution can significantly affect the HPG axis, disrupt migrantiae and reduce the number of miyanids within the epididymis.
The new study reveals a potential biological mechanism by which air pollution affects the number of mimi seeds: impairing the occurrence of miko by causing inflammation in the brain.
In the study, the researchers conducted a controlled experiment on healthy mice and mice lacking neurospecific inflammatory markers in their brains, tested their miyanid numbers after exposing them to air pollution, and found that air pollution exposure led to a significant increase in the expression of hypothalamic pro-inflammatory cytokines, followed by inhibition of the HPG axis to disrupt miyanogenesis.
This research has sounded the alarm bell for human beings, the harm caused by environmental pollution is immeasurable, in addition to creating a more harsh living environment, it will also be fed back from all aspects of human life, for a better future for mankind, the belief in protecting the environment should be engraved in everyone's heart!
▲Image source: giphy
Parthenogenesis has been achieved?
No man can have children!
In recent years, with the development of the economy and the emancipation of the mind, getting married and having children is no longer a necessary option in our lives, but there are also many people who do not like to be bound by marriage, but they like children or want to have their own offspring, so there are more and more women who pay attention to the topic of single childbearing, I believe many of you have had this idea.
Single birth, you all know, what about parthenogenesis ?) and parthenogenesis? Have you ever heard of it? It refers to the reproductive mode of the eggs of female animals or plants, which do not undergo the fertilization process, but develop into offspring alone, which belongs to asexual reproduction, but is slightly different from general asexual reproduction.
Yes, the setting of parthenogenesis is like a daughter country, where girls drink the water of the Zimu River and can have children without a man. However, mammals represented by humans have always used sexual reproduction as a method of reproduction, hindered by imprinted genes, and parthenogenesis should not exist in nature.
But scientists' tireless exploration has given life endless possibilities, and last month, a team from Yanchang Wei, affiliated with Shanghai Jiao Tong University School of Medicine, published a study titled "Viable offspring derived from single unfertilized mammalian oocytes" in the PNAS.
▲Image source: References[2]
In this study, the researchers used gene editing to modify the methylation of the imprint control area to achieve the cultivation of mammalian offspring using only a single, unfertilized oocyte, and mice could live to adulthood and give birth to offspring. This is the first mammal to develop using "single" unfertilized oocytes in an experiment with unisex reproductive offspring.
During reproduction, most genes in mammals inherit two copies of genetic information from both parents, but there are some special and very few genes that only transcribe or express the genetic information of one of the parents, and the other does not express or express very little, which is the imprinted gene.
In parthenogenesis, the embryo does not have a mark gene from the paternal line, which doubles the specific imprint of the mother, which makes the embryo almost unable to develop, so this is why we said above that the obstruction of the imprint gene makes it impossible for parthenogenesis in nature.
However, in this study, in order to make the lone and female cells develop smoothly, the researchers rewrote the oocyte genes of mice, methylated and edited 7 important imprint control areas in oocytes, so that the egg cells directly entered the fertilized state and became parthenogenetic embryos, and then after in vitro embryo culture and transfer of blastocysts to female mice, 3 small mice were finally successfully born.
Although the experiment has been successful, but the whole parthenogenetic reproductive technology still has many defects, such as low reproductive efficiency, ethical issues remain unresolved, etc., without the participation of the other sex can also have a "beautiful vision" may take many years of research to be applied, but hope or to have, the future is also bright, I believe that the development of science and technology in the future will bring more choices and possibilities to human beings!
▲Image source: giphy
The secret of female orgasm
Made clear by 12 rabbits?
For female orgasm, everyone's experience is different, some girls are suffering from their own difficulty in reaching orgasm, some girls hope that they are not so sensitive, but the physiological mechanism behind it has always made researchers feel puzzling: why does female orgasm exist?
Its existence is intriguing for two main reasons, on the one hand, unlike male orgasms, female orgasms are not necessary for reproduction, on the other hand, this neuroendocrine reflex is too complex to be an evolutionary accident.
Scientists have proposed multiple types of evolutionary explanations, most of which are not supported by sound arguments, while a paper published in the Proceedings of the National Academy of Sciences (PNAS), "An experimental test of the ovulatory homolog model of female orgasm," explores the problem in depth and provides experimental evidence.
▲Image source: References[3]
The reproductive mechanism of mammals such as rabbits and cats in nature is different from that of humans, they do not spontaneously ovulate, but need to mate to stimulate ovulation, and the ovulation homologous model of female orgasm believes that the neuroendocrine mechanism of female orgasm evolved from the mechanism of mating to induce ovulation in some mammals, and is homologous with these mechanisms.
To test this claim, a team of researchers from Yale University conducted an experiment on rabbits, and they believed that drugs that can affect orgasm in humans, such as fluoxetine (a commonly used antidepressant drug that causes women to lose libido, delay or loss of orgasm), should also affect the ovulation of animals with mating-induced ovulation mechanisms, such as rabbits.
The researchers gave fluoxetine to female rabbits for 2 consecutive weeks, and then let the experimental rabbits mate with male rabbits, and found that taking fluoxetine reduced the number of ovulations after mating by 30%.
In the second experiment, they gave a single injection of human chorionic gonadotropin to induce ovulation in rabbits who had taken fluoxetine, and the number of ovulations was reduced by only 8%, indicating that intervention at the brain level could affect the ovulation behavior of rabbits, confirming the homologous model of ovulation in women.communion.
Although the rabbit experiment sounds interesting, there is still a lot of controversy in this study, such as the sample size of 12 rabbits is too small, the 30% change in ovulation volume is small, and whether the rabbit has an orgasm or not.
In short, there is still no consensus in the academic community on the mechanism of female orgasm, and more and deeper research may expect more scientists to continue to explore.
▲Image source: giphy
Extending the optimal age for childbearing?
Maybe it can become a reality!
We all know that in a physiological sense, women do have the optimal age for childbearing.
There have been clinical research data to prove that women between 30 and 35 years old is the lowest risk of pregnancy complications in the age of age, after 35 years old, the probability of abnormal development of embryonic chromosomes will show a substantial increase, ovarian function will also decline rapidly, the number of ovaries that can mature in the ovaries is reduced. Therefore, the current definition of the optimal reproductive age in clinical practice generally refers to women between the ages of 20 and 34.
But this age stage is generally the golden age of many people's career and academic development, many women are not willing to interrupt their dreams to go home and have children, so is there any way to extend the best reproductive period for women, so that women can maintain high-quality eggs even if they are thirty or forty years old?
Researchers from the Department of Genetics at the Hebrew University of Jerusalem (HUJI) published a study in the journal Genetics titled Progression of meiosis is coordinated by the level and location of MAPK activation via OGR-2 in Caenorhabditis elegans. New arguments are provided for this possibility.
▲Image source: References[4]
The study used a very important organism, Caenorhabditis elegans, a non-parasitic nematode with a transparent body, about 1 mm in length, mainly distributed in the soil of temperate regions, and its lifespan is about two to three weeks. They contain the same number of genes as humans, and eggs mature in a day, playing an important role in helping scientists understand human genetics.
The researchers monitored the maturation of Caenorhabditis elegans eggs and found a gene that controls the rhythm of egg maturation, ogr-2, in the law of gene changes during egg maturation, and further studied MAP kinase (MAPK), which drives egg generation.
When researchers used gene editing to remove the ogor-2 gene, MAPK overdrived, and the eggs of Caenorhabditis elegans quickly aged, and aging egg cells were the leading cause of birth defects, miscarriage and infertility.
This means that scientists have discovered important mechanisms that control ovarian development and oocyte senescence! Although this research is still in its early stages, it is believed that as the research progresses, delaying the date of egg maturity is just around the corner, and even older women will be able to maintain high-quality eggs and increase the chances of having a healthy baby!
▲Image source: giphy
Well, today's research sharing is here, what new knowledge and new research do you want to know or be interested in, welcome to tell us in the comments section Oh ~
If you think the popular science content is still good or helpful to you, welcome to forward the circle of friends, family group, or click a concern or like! Thank you all for your encouragement!
I love the world.
bibliography
[1] Qiu L, Chen M, Wang X, et al. PM 2. 5 Exposure of Mice during Spermatogenesis: A Role of Inhibitor κ B Kinase 2 in Pro-Opiomelanocortin Neurons[J]. Environmental health perspectives, 2021, 129(9): 097006.
[2] Wei Y, Yang C R, Zhao Z A. Viable offspring derived from single unfertilized mammalian oocytes[J]. Proceedings of the National Academy of Sciences, 2022, 119(12): e2115248119.
[3] Pavlicev M, Zupan A M, Barry A, et al. An experimental test of the ovulatory homolog model of female orgasm[J]. Proceedings of the National Academy of Sciences, 2019, 116(41): 20267-20273.
[4] Achache H, Laurent L, Hecker-Mimoun Y, et al. Progression of meiosis is coordinated by the level and location of MAPK activation via OGR-2 in Caenorhabditis elegans[J]. Genetics, 2019, 212(1): 213-229.