The female reproductive tract is a complex microenvironment with folded epithelium that offers various signals to allow fertilization. The tract’s complex shape increases its surface area, improving nutrient transport and creating a better environment for supporting and fertilizing eggs. The fluid in the fallopian tubes comes from blood plasma and includes nutrients and proteins released by the lining cells.
The properties of the extracellular fluid in the female reproductive tract change over time and space, but how these changes affect the behavior of the epithelial cells lining the tract is not yet known.
A new study from Monash University offers significant insights into the development of the female reproductive tract and fertility. Engineers revealed that epithelial cells respond to the elevated viscosity of culture media by modulating their development and functionality to enhance cilia formation and coordination.
The study offers important clues on how changes in the ‘stickiness’ or viscosity of the fluid in the female reproductive tract influence how cells are modified to facilitate the transport of eggs for fertilization.
Melati Abdul Halim, a PhD candidate in the Department of Mechanical and Aerospace Engineering, said, “Imagine the difference between walking through water versus thick mud. This is what it’s like for tiny cells in the female reproductive tract, where the stickiness of the fluid can vary.”
The thicker fluid creates extra resistance, which causes the cells to change their behavior. Some cells start growing cilia, a tiny hair-like structure, which helps them move things like eggs along the reproductive tract.
The fluid’s thickness causes the cells to produce more cilia, and their movements become more coordinated. This coordinated beating pattern can facilitate the formation of metachronal waves, which are essential for the transport of eggs and embryos.
Corresponding and senior author Dr. Reza Nosrati said the findings suggest that the natural stickiness of fluid in our bodies could play a key role in processes like fertilization.
“The study suggests that the elevated viscosity at certain stages of the menstrual cycle could be a natural mechanism to enhance the formation and coordination of cilia, thus facilitating fertilization. This important aspect of natural fertilization and the role of higher viscosity fluid in the reproductive tract may need more careful evaluation as part of infertility diagnosis and assisted reproduction practices,” Dr. Nosrati said.
“It provides insights into how the viscosity (thickness, stickiness) of extracellular fluid influences the behavior of epithelial cells lining the fallopian tubes and could be key to understanding and potentially treating fertility issues.”
Journal Reference:
- Abdul Halim, M.S., Dyson, J.M., Gong, M.M. et al. Fallopian tube rheology regulates epithelial cell differentiation and function to enhance cilia formation and coordination. Nat Commun 15, 7411 (2024). DOI: 10.1038/s41467-024-51481-9
