title: L-arginine supplementation prevents increases in intestinal permeability and bacterial translocation in male Swiss mice subjected to physical exercise under environmental heat stress.
abstract: Dietary supplementation with l-arginine has been shown to improve the intestinal barrier in many experimental models. This study investigated the effects of arginine supplementation on the intestinal permeability and bacterial translocation (BT) induced by prolonged physical exercise under heat stress. Under anesthesia, male Swiss mice (5-wk-old) were implanted with an abdominal sensor to record their core body temperature (T(core)). After recovering from surgery, the mice were divided into 3 groups: a non-supplemented group that was fed the standard diet formulated by the American Institute of Nutrition (AIN-93G; control), a non-supplemented group that was fed the AIN-93G diet and subjected to exertional hyperthermia (H-NS), and a group supplemented with l-arginine at 2% and subjected to exertional hyperthermia (H-Arg). After 7 d of treatment, the H-NS and H-Arg mice were forced to run on a treadmill (60 min, 8 m/min) in a warm environment (34°C). The control mice remained at 24°C. Thirty min before the exercise or control trials, the mice received a diethylenetriamine pentaacetic acid (DTPA) solution labeled with technetium-99m ((99m)Tc-DTPA) or (99m)Tc-Escherichia coli by gavage to assess intestinal permeability and BT, respectively. The H-NS mice terminated the exercise with T(core) values of ∼40°C, and, 4 h later, presented a 12-fold increase in the blood uptake of (99m)Tc-DTPA and higher bacterial contents in the blood and liver than the control mice. Although supplementation with arginine did not change the exercise-induced increase in T(core), it prevented the increases in intestinal permeability and BT caused by exertional hyperthermia. Our results indicate that dietary l-arginine supplementation preserves the integrity of the intestinal epithelium during exercise under heat stress, acting through mechanisms that are independent of T(core) regulation.
authors.affiliation: Department of Foods, Faculty of Pharmacy.
authors.forename: Kátia Anunciação
authors.initials: KA
authors.lastname: Costa
authors.forename: Anne Danieli Nascimento
authors.initials: AD
authors.lastname: Soares
authors.forename: Samuel Penna
authors.initials: SP
authors.lastname: Wanner
authors.forename: Rosana das Graças Carvalho dos
authors.initials: Rd
authors.lastname: Santos
authors.forename: Simone Odília Antunes
authors.initials: SO
authors.lastname: Fernandes
authors.forename: Flaviano dos Santos
authors.initials: Fdos S
authors.lastname: Martins
authors.forename: Jacques Robert
authors.initials: JR
authors.lastname: Nicoli
authors.forename: Cândido Celso
authors.initials: CC
authors.lastname: Coimbra
authors.forename: Valbert Nascimento
authors.initials: VN
authors.lastname: Cardoso
mesh_terms: D000818:Animals; D001120:Arginine / Q000494:pharmacology / Q000627:therapeutic use*; D018988:Bacterial Translocation / Q000187:drug effects*; D001831:Body Temperature / Q000187:drug effects; D019587:Dietary Supplements; D004926:Escherichia coli; D005334:Fever / Q000150:complications* / Q000473:pathology; D006358:Hot Temperature; D007413:Intestinal Mucosa / Q000187:drug effects* / Q000382:microbiology / Q000473:pathology; D007422:Intestines / Q000187:drug effects* / Q000382:microbiology / Q000473:pathology; D008099:Liver / Q000382:microbiology; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D004369:Pentetic Acid / Q000097:blood; D010539:Permeability; D010805:Physical Conditioning, Animal / Q000502:physiology*; D012420:Running / Q000502:physiology; D013312:Stress, Physiological
chemical_list: D004369:Pentetic Acid; D001120:Arginine