title: Creatine supplementation attenuates corticosteroid-induced muscle wasting and impairment of exercise performance in rats.
abstract: The objective of the present study was to investigate whether creatine (Cr) could attenuate the deleterious effects of high doses of dexamethasone (Dexa) on body mass, exercise performance, and respiratory variables of rodents. Forty-four Wistar rats performed incremental maximal exercise tests. They were then assigned to four groups: G1: subcutaneous (s.c.) and intraperitoneal (i.p.) saline; G2: s.c. saline and i.p. Cr (250 mg x kg(-1) x day(-1)); G3: s.c. Dexa (7.5 mg x kg(-1) x day(-1)) and i.p. saline; G4: s.c. Dexa and i.p. Cr. New exercise tests and analysis of the respiratory pattern under resting conditions and after stimulation with doxapram (2 mg/kg i.p.) were performed after 18 days. Post- minus pretreatment differences were compared between groups. G3 and G4 showed a significant impairment in body mass gain compared with G1 and G2 (P < 0.05) (G1: 65.3 +/- 26.1, G2: 93.1 +/- 27.4, G3: -18.4 +/- 20.1, G4: 9.8 +/- 23.1 kg x 10(-3)). Similar results were observed for maximal oxygen consumption (G1: 9.5 +/- 8.5, G2: 25.8 +/- 14.5, G3: -25.5 +/- 6.0, G4: -4.8 +/- 9.5 ml x kg(-1) x min(-1)) and test duration (G1: 43.0 +/- 45.0, G2: 72.0 +/- 59.5, G3: -165.0 +/- 60.6, G4: -48.0 +/- 48.5 s). Simultaneous use of Cr significantly attenuated the Dexa-induced impairment of the last two variables. Cr attenuated Dexa-induced gastrocnemius and diaphragm muscle weight losses and the atrophy of gastrocnemius type IIb fibers. Cr supplementation had only small effects on Dexa-induced respiratory changes. These results suggest that Cr may play a role in the prophylaxis or treatment of steroid-induced myopathy.
authors.affiliation: Dept. of Internal Medicine, Medical School of Ribeirão Preto, University of São Paulo, São Paulo, Brazil. jabmarti@fmrp.usp.br
authors.forename: Luciana Gomes
authors.initials: LG
authors.lastname: Menezes
authors.forename: Cláudia
authors.initials: C
authors.lastname: Sobreira
authors.forename: Luciano
authors.initials: L
authors.lastname: Neder
authors.forename: Antonio Luis
authors.initials: AL
authors.lastname: Rodrigues-Júnior
authors.forename: José A Baddini
authors.initials: JA
authors.lastname: Martinez
mesh_terms: D000305:Adrenal Cortex Hormones / Q000009:adverse effects*; D000818:Animals; D001835:Body Weight / Q000187:drug effects / Q000502:physiology; D003401:Creatine / Q000494:pharmacology / Q000627:therapeutic use*; D003907:Dexamethasone / Q000009:adverse effects*; D003964:Diaphragm / Q000187:drug effects / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D008297:Male; D018482:Muscle, Skeletal / Q000187:drug effects / Q000502:physiology; D009133:Muscular Atrophy / Q000139:chemically induced* / Q000503:physiopathology / Q000517:prevention & control*; D010101:Oxygen Consumption / Q000187:drug effects / Q000502:physiology; D010805:Physical Conditioning, Animal / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D015656:Respiratory Mechanics / Q000187:drug effects / Q000502:physiology; D013990:Tidal Volume / Q000187:drug effects / Q000502:physiology
chemical_list: D000305:Adrenal Cortex Hormones; D003907:Dexamethasone; D003401:Creatine