Effects of hydrochloric, acetic, butyric, and propionic acids on pathogenesis of ulcers in the nonglandular portion of the stomach of horses.
OBJECTIVE
To identify the pathogenesis of gastric ulcers by comparing injury to the nonglandular gastric mucosa of horses caused by hydrochloric acid (HCl) or volatile fatty acids (VFAs).


METHODS
Gastric tissues from 30 horses.


METHODS
Nonglandular gastric mucosa was studied by use of Ussing chambers. Short-circuit current (Isc) and potential difference were measured and electrical resistance calculated for tissues after addition of HCl and VFAs to normal Ringer's solution (NRS). Tissues were examined histologically.


RESULTS
Mucosa exposed to HCl in NRS (pH, 1.5) had a significant decrease in Isc, compared with Isc for mucosa exposed to NRS at pH 4.0 or 7.0. Also, exposure to 60mM acetic, propionic, and butyric acids (pH, 4.0 or 1.5) caused an immediate significant decrease in Isc. Recovery of sodium transport was detected only in samples exposed to acetic acid at pH 4.0. Recovery of sodium transport was not seen in other mucosal samples exposed to VFAs at pH < or = 4.0.


CONCLUSIONS
Acetic, butyric, and propionic acids and, to a lesser extent, HCl caused decreases in mucosal barrier function of the nonglandular portion of the equine stomach. Because of their lipid solubility at pH < or = 4.0, undissociated VFAs penetrate cells in the nonglandular gastric mucosa, which causes acidification of cellular contents, inhibition of sodium transport, and cellular swelling. Results indicate that HCl alone or in combination with VFAs at gastric pH < or = 4.0 may be important in the pathogenesis of gastric ulcers in the nonglandular portion of the stomach of horses.
Nadeau
Jenifer A
JA
Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996, USA.
Andrews
Frank M
FM
Patton
Clark S
CS
Argenzio
Robert A
RA
Mathew
Alan G
AG
Saxton
Arnold M
AM
D019342:Acetic Acid / Q000009:adverse effects*; D000818:Animals; D020148:Butyric Acid / Q000009:adverse effects*; D046508:Culture Techniques; D005232:Fatty Acids, Volatile / Q000009:adverse effects; D005260:Female; D005753:Gastric Mucosa / Q000187:drug effects / Q000473:pathology; D006734:Horse Diseases / Q000139:chemically induced* / Q000209:etiology / Q000473:pathology; D006736:Horses; D006851:Hydrochloric Acid / Q000009:adverse effects*; D006863:Hydrogen-Ion Concentration; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D011422:Propionates / Q000009:adverse effects*; D013270:Stomach / Q000187:drug effects* / Q000473:pathology; D013276:Stomach Ulcer / Q000139:chemically induced* / Q000209:etiology / Q000473:pathology / Q000662:veterinary*; D013997:Time Factors
D005232:Fatty Acids, Volatile; D011422:Propionates; D020148:Butyric Acid; C029658:propionic acid; D019342:Acetic Acid; D006851:Hydrochloric Acid