STUDIES ON ETHANOL-INDUCED SUBEPITHELIAL FLUID ACCUMULATION AND JEJUNAL VILLUS BLEB FORMATION - AN IN-VITRO VIDEO MICROSCOPIC APPROACH

Jejunal intraluminal ethanol causes morphological and mucosal microvas cular injury. The purpose of the present study was to understand the m echanism of the morphological alterations caused by ethanol without th e influence of ethanol's effect on the microcirculation. Therefore, we have investigated the ethanol-induced morphological changes in the ab sence of blood flow (i.e., in the jejunum in vitro) and compared these changes with those reported to occur in the presence of microcirculat ion (i.e., in the jejunum in vivo). The mucosa of jejunal segments was exposed to a control solution and to solutions containing 0.8, 1.6, a nd 4.8% (w/v) ethanol, using a specially designed apparatus. The morph ological response of the mucosa to these solutions was continuously ex amined employing a video microscopic technique, and the changes were m orphometrically evaluated on subsequent playback of videotapes. Ethano l caused a concentration-dependent increase in the number of villi wit h subepithelial fluid accumulation, i.e., blebs, and a decrease in the height of the villus core (i.e., lamina propria). With 0.8 and 1.6% e thanol, the contracted core remained partially attached to the epithel ium and the total villus height (villus core plus epithelial layer) de creased. With 4.8% ethanol, the villus core contraction was so rapid t hat the stroma fully separated from the epithelium. Thus, among other factors, the rapidity of the villus core contractions appears to play a role in the subepithelial bleb formation and in the appearance of th e bleb. The ethanol-induced changes in vitro are similar to those repo rted to occur in the jejunum in vivo. Therefore, we conclude that the effect of ethanol on morphology is independent of its action on the mi crocirculation.