Postnatal development of the mucosal plexus in the porcine small and large intestine

Abstract

Knowledge regarding the foetal and postnatal development of the enteric nervous system is crucial for the understanding of congenital disorders. While lot of information exists regarding the myenteric and submucosal plexuses, the development of the mucosal plexus has not been previously studied. The mucosal innervation seems to play an important role in the local reflex activity of the gut. In this study, we examined the development of enteric mucosal innervation in the pig at various ages of life. Small and large bowel paraffin-embedded specimens were stained with PGP 9.5 and neurofilament protein in three piglets from six age groups (60 and 90 days gestation, newborn, 4 and 12 weeks old, and adult pigs). Small and large bowel demonstrated identical innervation patterns. Myenteric and submucosal plexuses were stained with PGP 9.5 at 60 days gestation. However, the mucosal staining was first noted clearly at the newborn period. By 4 weeks, PGP 9.5 staining was noted in small amounts within the mucosa. Inner proprial and villous fibres were seen ahead in time to the subepithelial fibres. Both inner proprial and villous staining became quiet prominent by 12 weeks of age and remained unchanged into adulthood. However, the subepithelial fibres appear to increase in adulthood. This study demonstrates for the first time that enteric mucosal innervation first appears only at birth. The immaturity of the mucosa generated reflex activity, and secretory functions may have implication in the management of functional intestinal obstruction in the premature infant.

Postnatal and diet‐dependent increases in enteric glial cells and VIP‐containing neurones in preterm pigs

“…Neuroplastic changes in the ENS have been reported during perinatal development, mainly by counting numbers or percentages of immunoreactive perikarya in rodents 4 and pigs 18–20 . Rarely, alterations in nerve fibres or cell volume were evaluated during this period 19,31 . By using a stereological approach in this study we were able to provide new insights into global alterations in the ENS during postnatal development of the porcine small intestine.…”

“…[18][19][20] Rarely, alterations in nerve fibres or cell volume were evaluated during this period. 19,31 By using a stereological approach in this study we were able to provide new insights into global alterations in the ENS during postnatal development of the porcine small intestine. Earlier findings have indicated that each region of the gastrointestinal tract receives a different input from neurochemically coded enteric neuron subtypes in pigs 18,34,35 and humans.…”

“…The ENS of pigs at the level of the small intestine is organized in three ganglionated nervous networks: the myenteric plexus (MP), the outer submucous plexus (OSP) and inner submucous plexus (ISP). As PGP9.5 fails to stain mucosal fibres clearly in the newborn period, 31 βIII‐tubulin‐IR, a neuron‐specific cytoskeletal protein, was used. However, to evaluate its use as a general neuronal marker, we conducted a pilot study on three piglets in which we compared βIII‐tubulin Vv with that of PGP9.5.…”

“…Total bIII-IR + S100-IR in intestinal wall 31 bIII-tubulin-IR, a neuron-specific cytoskeletal protein, was used. However, to evaluate its use as a general neuronal marker, we conducted a pilot study on three piglets in which we compared bIII-tubulin Vv with that of PGP9.5.…”

Impaired intestinal barrier function and relapsing digestive disease: Lessons from a porcine model of early life stress

“…We know that the enteric nervous system (ENS) serves as the link between brain-gut axis and is intricately involved in visceral sensation, motility, absorption and secretion, and intestinal barrier function 29 . The ENS is hypo-mature at birth in both pigs and humans, and it undergoes significant postnatal changes 30,31 . There is remarkable plasticity in the ENS during the development and adaptive phases in early growth periods and alterations in these processes have the potential to lead to life-long alterations in GI physiology.…”