Normal histology and the effect of acute mechanical stress on the esophagus epithelium in the guinea pig

Abstract

With the aim of investigating histologically the effect of acute mechanical stress on keratinized mucosa of the guinea pig, examination of the esophagus was carried out on 50 adult animals. Twenty-eight served as normal controls, while in 22 animals the esophagus was dilated in vivo 10 min by means of polyethylene tubes of varying diameter before killing the animals. In histological sections from six non-dilated esophagi the length of the epithelio-mesenchymal border (basement membrane) was measured at a distance of 15 and 20 mm from the larynx. No difference was found when measured at the two levels in one and the same animal, whereas there was a significant variation between different animals. Macroscopically the esophageal mucosa showed a complex system of circularly arranged keratin crests, divided into segments. Histologically the configuration of the epithelium-connective tissue union showed a regularly scalloped pattern. The spinous cells were arranged in arcades stretching from one epithelial ridge to the next. The stratum granulosum was distinct with deeply stained keratohyalin granules. The stratum corneum was divided into a narrow heavily stained deeper zone and a loosely structured, lightly stained upper zone. In vivo dilation of esophagi resulted in a uniform flattening of the epithelium without break in continuity of the tissue. The scalloped epithelium-connective tissue boundary was evened out. The length of the basement membrane of the dilated esophagus was found to be considerably greater than in control animals. The investigation demonstrated that lining epithelium is pliable to a great extent and adapted for marked elongation.