Structural development of PGP9.5-immunopositive myenteric plexus in embryonic rats

Area of Science:

• Developmental biology
• Neuroscience
• Gastroenterology

Background:

• The myenteric plexus, a key component of the enteric nervous system, controls gastrointestinal motility.
• Understanding its development is crucial for deciphering the onset of intestinal function.

Purpose of the Study:

• To investigate the relationship between the 3-dimensional structural changes of the myenteric plexus and the initiation of functional intestinal movement in mammalian embryos.
• To map the developmental timeline of the enteric nervous system in the embryonic rat intestine.

Main Methods:

• Whole mounts of embryonic rat intestine were examined using confocal laser scanning microscopy.
• Immunostaining with anti-protein gene product 9.5 antibody was employed to visualize nerve cells and fibers.
• Structural changes were analyzed from embryonic day 12.5 to the neonatal period.

Main Results:

• Early nerve cell scattering was observed in the small intestine by embryonic day 12.5.
• Neuronal networks with large meshes formed in both intestines by embryonic day 13.5.
• Significant increases in nerve fiber number and decreases in mesh size occurred between embryonic days 13.5 and 16.5.
• Nerve cell arrangement became parallel to circular muscle fibers after embryonic day 16.5, coinciding with meconium passage.

Conclusions:

• The formation and maturation of the myenteric plexus correlate with the development of coordinated intestinal muscle contractions.
• This neural network development is essential for acquiring propulsive intestinal movements before birth.