title: The effect of a low dose of clenbuterol on rat soleus muscle submitted to joint immobilization.
abstract: The aim of the present study was to evaluate the effect of joint immobilization on morphometric parameters and glycogen content of soleus muscle treated with clenbuterol. Male Wistar (3-4 months old) rats were divided into 4 groups (N = 6 for each group): control, clenbuterol, immobilized, and immobilized treated with clenbuterol. Immobilization was performed with acrylic resin orthoses and 10 microg/kg body weight clenbuterol was administered subcutaneously for 7 days. The following parameters were measured the next day on soleus muscle: weight, glycogen content, cross-sectional area, and connective tissue content. The clenbuterol group showed an increase in glycogen (81.6%, 0.38 +/- 0.09 vs 0.69 +/- 0.06 mg/100 g; P < 0.05) without alteration in weight, cross-sectional area or connective tissue compared with the control group. The immobilized group showed a reduction in muscle weight (34.2%, 123.5 +/- 5.3 vs 81.3 +/- 4.6 mg; P < 0.05), glycogen content (31.6%, 0.38 +/- 0.09 vs 0.26 +/- 0.05 mg/100 mg; P < 0.05) and cross-sectional area (44.1%, 2574.9 +/- 560.2 vs 1438.1 +/- 352.2 microm(2); P < 0.05) and an increase in connective tissue (216.5%, 8.82 +/- 3.55 vs 27.92 +/- 5.36%; P < 0.05). However, the immobilized + clenbuterol group showed an increase in weight (15.9%; 81.3 +/- 4.6 vs 94.2 +/- 4.3 mg; P < 0.05), glycogen content (92.3%, 0.26 +/- 0.05 vs 0.50 +/- 0.17 mg/100 mg; P < 0.05), and cross-sectional area (19.9%, 1438.1 +/- 352.2 vs 1724.8 +/- 365.5 microm(2); P < 0.05) and a reduction in connective tissue (52.2%, 27.92 +/- 5.36 vs 13.34 +/- 6.86%; P < 0.05). Statistical analysis was performed using Kolmogorov-Smirnov and homoscedasticity tests. For the muscle weight and muscle glycogen content, two-way ANOVA and the Tukey test were used. For the cross-sectional area and connective tissue content, Kruskal-Wallis and Tukey tests were used. This study emphasizes the importance of anabolic pharmacological protection during immobilization to minimize skeletal muscle alterations resulting from disuse.
authors.affiliation: Departamento de Fisioterapia, Universidade Federal de São Carlos, São Carlos, SP, Brasil.
authors.forename: K M
authors.initials: KM
authors.lastname: Cancelliero
authors.forename: J L Q
authors.initials: JL
authors.lastname: Durigan
authors.forename: R P
authors.initials: RP
authors.lastname: Vieira
authors.forename: C A
authors.initials: CA
authors.lastname: Silva
authors.forename: M L O
authors.initials: ML
authors.lastname: Polacow
mesh_terms: D000318:Adrenergic beta-Agonists / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D002976:Clenbuterol / Q000008:administration & dosage / Q000494:pharmacology*; D003238:Connective Tissue / Q000187:drug effects*; D006003:Glycogen / Q000032:analysis*; D007103:Immobilization; D008297:Male; D018485:Muscle Fibers, Skeletal / Q000187:drug effects; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D009133:Muscular Atrophy / Q000517:prevention & control; D009929:Organ Size / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
chemical_list: D000318:Adrenergic beta-Agonists; D006003:Glycogen; D002976:Clenbuterol