The histologic development of acid-induced esophagitis in the cat

Acute reflux esophagitis in man is characterized histologically by infiltrates of segmented leukocytes, epithelial proliferation, and ulcers. Our feline model, which includes each of these features, is produced by the infusion of 0.1 N HCl at a rate of 1 ml per min into the distal esophagus of adult cats for varying periods of time. Our histologic scoring system includes both the intensity and the distribution of four morphologic features, namely basal cell hyperplasia (BCH), intraepithelial segmented leukocytes (IEL), subepithelial leukocytes (SEL), and ulcers. Each of these four categories are scored from 0 to 4, with a potential score of 16. We evaluated the effects of duration of acid exposure by infusing cats with HCl for 5 min (N = 4), 15 min (N = 12), 20 min (N = 12), and 30 min (N = 6), followed by autopsy 24 h later. Mean scores (+/- SE) were as follows: 5 min, 3.0 (+/- 1.7); 15 min, 9.0 (+/- 1.0); 20 min, 11.17 (+/- 1.06); 30 min, 15.17 (+/- 0.54). Differences between 5 and 15 min, 15 and 30 min, and 20 and 30 min were significant (P less than 0.05). Basal cell hyperplasia appeared to be the most sensitive marker of acid injury; ulcers denoted severe injury associated with longer exposure periods. Although an occasional eosinophil was seen, the majority of the segmented leukocytes were neutrophils. We also studied healing histologically by examining cats at 1 d (N = 6), 2 d (N = 6), 3 d (N = 11), and 4 d (N = 6) after a 30 min exposure to HCl.(ABSTRACT TRUNCATED AT 250 WORDS)