Morphometric analysis of muscularis proper and myenteric plexus of the normal human oesophagus. Age related changes.

BACKGROUND

Oesophagus is a muscular tube that transports food and liquids by coordinated contraction of its muscular lining led by stimuli from the nerve plexus. Its muscularis proper layer consists of muscle cells, connective tissue and myenteric plexus. The aim of our histomorphometric study was to reveal detailed characteristics of this layer, cell number, volume, orientation, properties of myenteric plexus as well as changes related to aging.

MATERIALS AND METHODS

Oesophagus tissue samples from 17 male cadavers were taken from the cranial and thoracic parts. Samples were divided in 2 groups: younger(ages 21-45) and older (ages 66-78). The tissue was routinely processed,embedded and serially sectioned. Sections were stained with Masson-Goldner and Cresyl-violet dyes. Digital images were analysed with the image analysis software.Statistics were performed with SPSS software.

RESULTS

The average thickness of the cranial part of the oesophageal wall and muscularis proper was 2590 μm and 1197 μm, respectively in the younger and 2453 μm and 1144 μm in the older group. Overall volume of the muscle tissue was slightly larger in the thoracic part, and in the younger group compared to the cranial part and the older group. The average number of the striated muscle cells per 100 μm in the cranial part was 771.5 and 749.7 in the younger and the older group, respectively. Striated cells were significantly less present only in the lower thoracic part of the oesophagus. In the older group,smaller striated muscle cells dominated over the larger ones. In the younger group, majority of the striated muscle cells were mid-sized. The thickness of the circular layer of muscularis proper was more affected by aging than the longitudinal one. Ganglion cells number was lower in the older group, but plexus area was unchanged.

CONCLUSIONS

Aging affects muscularis proper and myenteric plexus of the oesophagus.Major differences can be observed in the striated muscle cells size, volume of the circular layer and number of the ganglionic cells in the myenteric plexus.