We use cookies to help provide and enhance our service and tailor content and ads. Our results are consistent with in vitro observations reported previously by Perrone et al. Baar et al. **P < 0.01 treated vs. control rat muscles. 2, Canadian Journal of Physiology and Pharmacology, Vol. The process of muscle regeneration requires the influence of growth factors and a sequence of cellular events, which results in the regulation of the satellite cell population. Activated satellite cells were identified as BrdU-positive cells within the laminin-positive basal lamina surrounding muscle fibers. 3, the results were virtually identical to those detected using immunocytochemistry of muscle sections shown in Fig.

468, No. The shear created was hypothesized to stimulate synthesis of NO by NOS colocalized with the dystrophin-glycoprotein complex beneath the sarcolemma (10). 370, No. NOx in muscle extracts from unstretched contralateral control muscles was not significantly different from that from normal control muscles from rats that were not subjected to stretch treatment. Satellite cells are located on the outer surface of the muscle fiber, between the sarcolemma and basal lamina (see Diagram 1). The last important observation from these experiments is that the release of HGF was dependent on NO synthesis (26). This process is triggered by the stress of muscle damage/overload-induced resistance training. 38, No. 5, Journal of Cellular Biochemistry, Vol. Because small amounts of HGF were detectable in the unstretched control samples, we hypothesized that stretch may release HGF that enters the circulation and can be detected in other muscles that are not stretched.

In stretched muscles and in stretched muscles from d-NAME-treated rats, NOS activity was significantly increased (P < 0.01). 9, Biochimica et Biophysica Acta (BBA) - General Subjects, Vol. The involvement of NO was investigated by administering nitro-l-arginine methyl ester (l-NAME) or the inactive enantiomer NG-nitro-d-arginine methyl ester HCl (d-NAME) before stretch treatment. The BrdU labeling index increased in a dose-dependent manner with increasing concentrations of SME from 0 to 0.5 mg/ml, whereas extracts from control muscles did not stimulate satellite cell activation. Briefly, vastus, adductor, and gracilis muscles were excised, trimmed of fat and connective tissue, hand minced with scissors, and digested for 1 h at 37°C with 1.25 mg/ml Protease Type XIV. -nitro- Myonuclear accretion, i.e. The role of satellite cells in muscle hypertrophy. Extracts from stretched muscles contained the active form of HGF, and the satellite cell-activating activity could be neutralized by incubation with anti-HGF antibody. All experiments involving animals were conducted according to The Guidelines for the Care and Use of Laboratory Animals (enacted August 13, 1997, by the Graduate School of Agriculture, Hokkaido University, Hokkaido, Japan) and with the approval of the University of Arizona Institutional Animal Care and Use Committee. l-NAME treatment abolished satellite cell activation in stretched and contralateral unstretched muscles as shown qualitatively in Fig. 7, Exercise and Sport Sciences Reviews, Vol.

These experiments also demonstrated that HGF was associated with satellite cells at 12 h postplating, the time when stretch treatment was applied. A: increasing concentrations of stretched muscle (•) and control muscle extract (○) were added to medium at time of plating. 6, 23 May 2011 | Muscle & Nerve, Vol. SME was subjected to SDS-PAGE on 10% polyacrylamide gels under reducing conditions (25). *P < 0.05. For each in vivo stretch experiment, three 9-mo-old Sprague-Dawley male rats were used. 4, Biochemical and Biophysical Research Communications, Vol. Satellite cells were isolated from 9-mo-old male Sprague-Dawley rats according to the method described previously by Allen et al. 5, The International Journal of Biochemistry & Cell Biology, Vol. 2, The International Journal of Biochemistry & Cell Biology, Vol. 4A). More than 30% of the satellite cells harvested from stretched muscles had incorporated BrdU in vivo before harvest. 29, No. 5). Fig.