Changes in Gastric Function and Healing of Chronic Gastric Ulcers in Aged Rats

Abstract

ABSTRACT-The present study was designed to determine the relationship between changes in gastric function caused by aging and the healing of gastric ulcers. Male Fischer-344 rats (young, 2 months; aged, 24-26 months) were used. Gastric ulcers were induced by luminal application of an acetic acid solution (60%, 0.2 ml, 45 sec). The basal and histamine-stimulated gastric acid secretions in aged animals were significantly lower than those in young animals. However, the serum gastrin levels were almost the same in the two groups. Gastric mucosal blood flow and mucosal cell proliferation were also decreased in aged animals. Gastric contractile activity induced by electrical vagal stimulation was almost the same in the two groups, while the gastric relaxative response was significantly reduced in aged animals. The development and healing rate of gastric ulcers in aged animals were almost the same as those in young animals. Histologically, regeneration of the ulcerated mucosa was significantly reduced and tissue contraction occurred in aged animals, as compared to in young animals. We concluded that aging had little or no influence on the development and healing rate of gastric ulcers in rats, but the quality of ulcer healing was quite different between young and aged animals, probably resulting from various gastric dysfunctions related to ulcer healing. It is well-known that aging causes many functional changes in the body. Several investigators have already reported changes in functions such as gastric secretion (1, 2) and the serum gastrin level (3 -6), gastric mucosal blood flow (7), bicarbonate secretion (8), and mucosal cell proliferation (4) in the stomach of aged animals. O'Brien et al. (9) reported that aging had no influence on the spontaneous healing of acetic acid ulcers in 2-and 12-monthold rats. In general, gastric acid secretion, gastric mucosal blood flow and mucosal cell proliferation are considered to be profoundly involved in ulcer healing (10). Recently, we reported the importance of tissue contraction in the healing of gastric ulcers in rats (11,12). The aim of this study was to compare the functional changes in the stomachs of young (2-month-old) and aged (24-to 26-month-old) rats and to compare the development and healing of chronic gastric ulcers in the two groups. AnimalsYoung (2-month-old, 180 -200 g) and aged (24-to 26-month-old, 420-450 g) male Fischer-344 rats (Charles River, Kanagawa) were used. The animals had free access to laboratory rat chow (CE-2; Nihon Clea, Osaka) and tap water. The animals were deprived of food for 24 hr before the experiments unless stated otherwise. Drinking water was freely available to the animals up to 2 hr before the experiments. During fasting, all animals were kept in mesh-bottom cages to prevent coprophagy. All experiments were performed with paired young and aged animals, and 4 to 10 animals were used for each group. Induction of acetic acid-induced gastric ulcersAcetic acid-induced gastric ulcers were induced by luminal application of an acetic acid so...

Exacerbatory mechanism responsible for water immersion stress‐induced gastric lesions in aged rats compared with young rats

“…Tsukimi and Okabe 18 have reported that ageing does not significantly affect the development and healing rate of acetic acid‐induced gastric ulcers in rats. They suggested that this could be explained by the counterbalance of positive and negative components for ulcer healing.…”

An Overview of Acetic Acid Ulcer Models<br>&mdash;The History and State of the Art of Peptic Ulcer Research&mdash;

“…Due to its lack of adhesion, the mounting of stomachs with Type 3 ulcers to Lucite chambers is easier than with Type 1 or Type 2 ulcers. Our group 22) also examined the changes in gastric function and healing of acetic acid gastric ulcers in older rats. We found that aging had little or no influence on the development and healing rate of gastric ulcers, but the quality of ulcer healing was quite different between younger (2 month old) and older (24-26 month old) rats.…”

Comparison of Indomethacin, Diclofenac and Aspirin-Induced Gastric Damage according to Age in Rats

“…Experimental and limited clinical studies indicate that aging gastric mucosa has impaired mucosal defenses such as decreased mucus and bicarbonate secretion,17-19 decreased prostaglandin generation,15,20,21 reduced nitric oxide synthase activity,17,22 and reduced blood flow 23,24. Furthermore, aging increases the susceptibility to injury by a variety of damaging agents such ethanol7,23 as well as NSAIDs,25,26 and also impairs the healing of acute injury and chronic gastric ulcers 15,27…”