Acute Aerobic Swimming Exercise Induces Distinct Effects in the Contractile Reactivity of Rat Ileum to KCl and Carbachol

Abstract

Aerobic exercise promotes short-term physiological changes in the intestinal smooth muscle associated to the ischemia-reperfusion process; however, few studies have demonstrated its effect on the intestinal contractile function. Thus, this work describes our observations regarding the influence of acute aerobic swimming exercise in the contractile reactivity, oxidative stress, and morphology of rat ileum. Wistar rats were divided into sedentary (SED) and acutely exercised (EX-AC) groups. Animals were acclimated by 10, 10, and 30 min of swimming exercise in intercalated days 1 week before exercise. Then they were submitted to forced swimming for 1 h with a metal of 3% of their body weight attached to their body. Animals were euthanized immediately after the exercise section and the ileum was suspended in organ baths for monitoring isotonic contractions. The analysis of lipid peroxidation was performed in order to determinate the malondialdehyde (MDA) levels as a marker of oxidative stress, and intestinal smooth muscle morphology by histological staining. Cumulative concentration-response curves to KCl were altered in the EX-AC with an increase in both its efficacy and potency (Emax = 153.2 ± 2.8%, EC50 = 1.3 ± 0.1 × 10−2 M) compared to the SED group (Emax = 100%, EC50 = 1.8 ± 0.1 × 10−2 M). Interestingly, carbachol had its efficacy and potency reduced in the EX-AC (Emax = 67.1 ± 1.4%, EC50 = 9.8 ± 1.4 × 10−7 M) compared to the SED group (Emax = 100%, EC50 = 2.0 ± 0.2 × 10−7 M). The exercise did not alter the MDA levels in the ileum (5.4 ± 0.6 μ mol/mL) in the EX-AC compared to the SED group (8.4 ± 1.7 μ mol/mL). Moreover, neither the circular nor the longitudinal smooth muscle layers thickness were modified by the exercise (66.2 ± 6.0 and 40.2 ± 2.6 μm, respectively), compared to the SED group (61.6 ± 6.4 and 34.8 ± 3.7 μm, respectively). Therefore, the ileum sensitivity to contractile agents is differentially altered by the acute aerobic swimming exercise, without affecting the oxidative stress and the morphology of ileum smooth muscle.

The effects of exhaustive swimming and probiotic administration in trained rats: Oxidative balance of selected organs, colon morphology, and contractility

“…Only 4-week swimming exercise reduces the circular muscle layer, but increases longitudinal muscle layer and lipid peroxidation of the ileum (3). Similarly, acute aerobic exercise reduces both efficacy and relative potency of carbachol in the ileum of rats, but lipid peroxidation and the muscular layer of ileum does not change (2). This study also indicates that exercise reduced the ACh efficacy or sensitivity, because the pD2 value of ACh was lower in exercise groups compared to sedentary groups (p < 0.001).…”

“…Ischemia-reperfusion events during aerobic training induce some changes in the intestinal morphology, contractile activity, and oxidative variables. These changes are associated with the type, severity, and duration of exercise (2,3,11,38). In mice, intensive treadmill exercise for 4 days causes mucosal degenerations and a prominent (37%) reduction of the muscular layer of the ileum as well as reduced efficacy against contractile agents (carbachol and KCl).…”

Spirulina Platensis Supplementation Coupled to Strength Exercise Improves Redox Balance and Reduces Intestinal Contractile Reactivity in Rat Ileum

“…However, concerning the gastrointestinal tract, little is known about the effects of physical exercise. The exercise promotes ischemia and motor changes in the intestine and intestinal mucosa [35], and shows that swimming as an acute and chronic aerobic exercise reduces ileum reactivity to both KCl and CCh [15,16]; however the influence of anaerobic exercise of resistance was not evaluated so far.…”

“…Studies of acute and chronic swimming exercise have shown that acute exercise does not promote oxidative stress in rat ileum. Furthermore, there is an increase after four weeks of exercise, but after six to eight weeks, oxidative stress is reduced, showing that the body underwent physiological changes to adapt to exercise and returned to homeostasis [15,16]. However, regarding the strength exercise, there are not data showing its effect on the balance oxidative stress and antioxidant defenses.…”

“…Physical exercise has been recommended as a therapeutic tool for the prevention and treatment of diseases and disorders of the gastrointestinal tract. The acute and chronic aerobic swimming exercise modifies the contractile gastrointestinal reactivity, thus contributing to the improvement of these gastrointestinal symptoms [15,16]. However, nothing has been demonstrated about the influence of anaerobic exercise of resistance on intestinal contractility, and the effects of the combination of exercise and S. platensis supplementation.…”