The uterus is the organ at the center of the image, while the ovary serves as a branch on both sides of the uterus and connects to the fallopian tube. Photo Source: Pixabay
In addition to pregnancy, the uterus is usually not spent too much time on research. Now scientists are exploring the complex links between the uterus, ovaries and brain to better understand the effects of removing these organs on a persons health.
A study found that mice that had their uterus removed were more likely to have a decline in working memory than mice that had undergone other types of gynecological surgery.
Donna Korol, a biologist who studies the neurological mechanisms of learning and memory, was not involved in the new study. The medical community has always considered the uterus to be just a babys house, he said. However, in view of the role of this organ in the production and regulation of hormones, peoples understanding of the uterus has gradually begun to change.
Generally speaking, the medical view is that the unpregnant uterus is dormant and some experts call ituseless, said Heather Bimonte-Nelson, a behavioral neuroscientist at Arizona State University. We believe that womens reproductive organs may have value beyond their reproductive capacity, so we hope to further evaluate the impact of the uterus.
About a third of women in the United States undergo hysterectomy before they are 60 years old, and most of them choose to have hysterectomy before menopause around 50 years old. This is the second most common operation for American women besides caesarean section. In about half of these operations, only the uterus was removed, while in the other half, the uterus and ovaries were removed. Ovarian preservation can prevent women from entering a sudden premature menopause after surgery. Ovarian removal may also be associated with an increased risk of heart disease and osteoporosis.
Previous studies have found that estrogen and other hormones produced by ovaries can help protect the nervous structure of the brain, while promoting cardiovascular, skin, bone and urogenital health. But the uterus and ovary are closely linked, and nerves connect the brain to the two reproductive organs. Several studies have begun to examine this link carefully to assess the relationship between hysterectomy and the risk of early-onset dementia. Were really just starting to see the uterus as a regulator of brain function, rather than focusing on the ovaries, Korol said.
Bimonte-Nelson and her laboratory graduate student and co-author Stephanie Koebele began their experiment by operating on 60 mice. One group only removed the uterus (hysterectomy), the other only removed the ovaries (ovariectomy), the third removed the uterus and ovaries, and the fourth group, the last group, underwent surgery without removing any organs. The surgical procedure performed by the researchers mimics the surgical procedure performed on humans.
Before Koebele and Bimonte-Nelson tested the mice, they recovered from surgery for six months. The researchers used a series of mazes to assess the spatial and working memory of each rodent. These mazes force mice to find submerged platforms and return to where they used to be. Koebele and Bimonte-Nelson wanted to assess the ability of mice to remember navigation cues and to remember the changes that researchers made to the maze during the experiment.
They found that only the mice with the uterus removed performed worse in the working memory maze than the other mice. Working memory, Bomonte-Nelson explains, is like short-term memory that needs to be updated. For example, just remembering a phone number is an example of short-term memory. To remember this number and then operate it in some way, such as adding numbers together, requires working memory.
About two months after the operation, scientists re-examined mice that still had ovaries. They found that although the physical structure of the ovaries remained unchanged, hormone levels were slightly different between the hysterectomized group and the unresected group. This suggests that excision of the uterus alone can cause the ovaries to produce slightly different hormones, at least for a short time after surgery.
Bimonte-Nelson and Koebele werent surprised by the huge difference between the hysterectomized group and the ovariectomized group. Bimonte-Nelson explained that the difference was that removing the uterus alone would destroy the ovarian-uterine-nerve connection, rather than completely removing the system. When the system is interrupted, the remaining organs attempt to return to normal, which may lead to hormonal changes seen by scientists in the hysterectomy group.
The fact that only two months after surgery meant that scientists could not draw conclusions about the long-term effects of hysterectomy on cognitive function. Its just an animal model study, so the results dont necessarily match exactly what happens to humans. Nonetheless, Korol said, the teams study represents a better understanding of the cutting-edge trends of menopause.
There are many things to learn, but one thing is clear: the uterus has other abilities than the ability to nurture a new life.
Source: Liable Editor of Netease Scientist: Qiao Junyi_NBJ11279