RESUMO
Alpha-actinins are located in the skeletal muscle Z-line and form actin-actin cross-links. It belongs to a highly conserved family of actin-binding proteins- the spectrin superfamily, which also contains the spectrins and dystrophin. Mammalian skeletal muscle has two isoforms: alpha-actinins-2 and alpha-actinins-3. However, the response of alpha-actinins to exercise training is little understood. This study examined the effects of 8 weeks of resistance training on muscle mass, ACTN3 [alpha-actinins-3] gene expression levels and fiber type composition in the flexor hallucis longus [FHL] muscle. Forty five female Sprague-Dawley rats [Initial body mass: 169.25 +/- 9 gr age: 3 month] were obtained and assigned to a control [C; n=18] or exercise training [T; n=22] and pilot [P; n=5] groups. The resistance training consisted of climbing a ladder carrying a load suspended from the tail and the weight increased progressively. Real-time PCR and Immunohistochemistry techniques were used to measure gene expression levels and myosin heavy chain [MyHC] composition, respectively. Following 8 weeks of training, we observed significant increase in absolute muscle mass in FHL [P=0.01]. Results showed that no significant difference was found in ACTN3 gene expression levels between training and control groups [P=0.852 respectively]. Also, Pearson coefficient didn't indicated any significant relationships in gene expression and Fiber type IIX in response to resistance training in FHL [r=0.12]. However, resistance training effects on sarcomeric proteins development, these results showed no effect of resistance training on alpha-actinins-3 levels. Although alpha-actinins-3 has an important function to produce and progress of force in sarcomere, but didn't changed significantly in response to resistance training
RESUMO
It is reported that some inflammatory markers are predictive factors for atherosclerosis in childhood and adolescence and cardiovascular disease in adulthood. We investigated whether markers of inflammation including: cytokine [Interleukin-6 [IL-6]], acute-phase reactant [C-reactive protein [CRP]], white blood cell [WBC] count and its subgroups are associated with maximal oxygen consumption [VO[2max]] in overweight and normal children. Subjects were 26 boys aged 11-14 years included in two groups of overweight [n=10] and normal weight [n=16] children. VO[2max] was measured employing an incremental graded exercise test. IL-6 and CRP levels as well as WBC count were measured. Multivariable regression was employed to evaluate whether inflammatory markers were associated with VO[2max]. Mean VO[2max] for all subjects [n=26] was 36.35 +/- 10.42 ml/kg/min. This rate was lesser for overweight subjects [25.77 +/- 5.04] than in normal weight children [41.54 +/- 5.96]. Log IL-6, log CRP, and WBC count were correlated with VO[2max]. Also subgroups of WBC including Leukocytes, Lymphocyte, Neutrophils, Monocytes and Eosinophils associated with VO[2max]. IL-6, CRP and WBCs were inversely associated with aerobic or cardiorespiratory fitness levels measured by VO[2max] in children. This was independent of BMI of the subjects