Effects of Voluntary Wheel Running on Vulnerability of Gastric Mucosa to Action of Ulcerogenic Stimuli in Rats

Abstract

Physical activity is crucial for maintaining health. Physical exercise and, especially, running improves physiological and psychological functions. Physical activity is a natural stressor activating the hypothalamic-pituitary-adrenocortical axis. Previously we have shown that preconditioning stress protects the gastric mucosa against ulcerogenic stimuli. The aim of the present study was to investigate the effects of voluntary wheel running on a vulnerability of the gastric mucosa to ulcerogenic stimuli. Three ulcerogenic models were used: 1) prolonged gastric ischemia/reperfusion (30 min occlusion of celiac artery followed by 3 h of reperfusion); 2) indomethacin administration (IM, 35 mg/kg, sc); 3) cold-restraint stress (10°C). The effects of a single (2 h/day) as well as regular voluntary wheel running (2 h/day, 5 days) on the gastric injury were studied. On a day of experiment preliminary fasted (24 h) rats were subjected voluntary wheel running (2 h), then, they were given back in their cages and kept at room temperature for 1 h before the onset of ulcerogenic stimulus (cold-restraint or IM) or anesthesia which was performed 20 min before the occlusion of celiac artery. Control animals were kept in their cages but were also subjected ulcerogenic stimulus. Ischemia/reperfusion (I/R)-induced gastric injury was examined 3.5 h after the onset of ischemia; stress- and IM-induced gastric erosions were evaluated 3 h after the onset of cold-restraint or 4 h after IM administration. A single as well as regular voluntary wheel running by itself caused an elevation of plasma corticosterone. Both a single and regular voluntary wheel running attenuated I/R induced gastric erosions but aggravated cold restraint-induced injury. At the same time a single voluntary wheel running increased the IM-induced gastric injury whereas regular voluntary wheel running for 5 days resulted in its reduction. Thus, a single voluntary wheel running had the gastroprotective effect on I/R-induced injury but proulcerogenic ones on the cold restraint- or IM-induced injury. An increase of running length till 5 days not only eliminated the proulcerogenic effect of a single running on IM-induced gastric erosions but resulted in the gastroprotective effect. At the same time the effects of voluntary running on cold-restraint- and I/R-induced gastric erosions (proulcerogenic and gastroprotective effects, respectively) were not dependent on the length of running. The data suggest that regular voluntary running is useful in protection of gastric mucosa against IM- and I/R-induced gastric injury but does not appear to be effective against ulcerogenic action of cold-restraint stress.