Myofibroblasts in the mucosal layer of the uterine tube.

This research examined the presence and distribution of contractile cells in the mucosal layer of the uterine tubes in various animals. Such cells, or myofibroblasts, may influence mucosal condition and motility, and thus impact gamete transport.

Objective and Methods

• The researchers aimed to investigate the presence and distribution of a certain type of contractile cell known as myofibroblasts, within the mucosal layer (lamina propria) of the uterine tubes of various mammals. This included cows, sheep, horses, pigs, dogs, cats, rabbits, and guinea pigs.
• The study particularly focused on identifying these cells through the presence of certain proteins, specifically alpha-smooth muscle actin, tropomyosin, desmin, smooth muscle myosin (heavy chain), and cytoskeletal proteins called vimentin and cytokeratin.

Findings: Distribution of Myofibroblasts

• The research found two key distribution patterns of cells that tested positive for alpha-smooth muscle actin:
  • These cells could be scattered freely throughout the mucosal lamina propria. This pattern was observed in the isthmic uterine tube segments in all the animals studied.
  • Alternatively, a distinct subepithelial layer of these positive cells could be seen.

Colocalization & Cell Classification

• In terms of colocalization, alpha-smooth muscle actin was found together with tropomyosin in all the species, desmin in horses and sheep, and smooth muscle myosin in sheep and cows.
• All cells that tested positive for these proteins were also found to be reactive with anti-vimentin but not with anticytokeratin. Therefore, these cells were classified as myofibroblasts—a type of cell known to promote wound healing through contractibility.

Implications

• The study’s findings imply that the contractile cells (myofibroblasts) identified in the uterine tube mucosa may influence the condition of the mucosa and its motility. This could consequently play a key role in the transportation of gametes (sperm and egg cells).
• The researchers observed a distinct subepithelial layer of alpha-actin and tropomyosin positive cells in the fimbriae of horses. However, in other species, the alpha-smooth muscle actin immunoreactivity in the subepithelial region was very weak.