Browsing by Subject "Oxidative stress."
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Item Effects of four weeks of daily soy milk or dairy milk ingestion on the exercise induced inflammatory and oxidative responses in plasma and skeletal muscle in a post-menopausal female population.(2009-08-24T20:26:23Z) Beavers, Kristen Marie.; Willoughby, Darryn Scott, 1963-; Health, Human Performance and Recreation.; Baylor University. Dept. of Health, Human Performance and Recreation.The process of senescence is associated with increasing inflammation and subsequent oxidative stress in the body, both of which can exert negative health effects at local and systemic levels. Attenuation of such processes with novel dietary countermeasures has major public health implications. Soyfoods, as a source of high quality protein, minimal saturated fat, and unique composition of isoflavones may improve such indices, although such effects in healthy older women are not well delineated. To explore this supposition, a single-blind, randomized, controlled trial was conducted on 31 postmenopausal women at Baylor University, Waco TX. After a two week run-in period, subjects were randomly assigned to consume three servings of vanilla soy (n=16) or reduced-fat dairy (n=15) milk per day for four weeks. Parameters of systemic inflammation (TNF-α, IL-1β, IL-6) and oxidative stress (SOD, GPx, COX-2) as well as expression of local inflammation-responsive genes (TNF-α, IL-1β, IL-6, COX-2, NF-κB) were measured prior to supplementation, at four weeks post supplementation, and after an eccentric exercise bout performed to elicit an inflammatory response. A significant group by time effect for plasma TNF-α was observed (p = 0.04), with TNF-α values for the soy group appearing to stay consistent during the exercise period, while the TNF-α values for the dairy group increased post-supplementation, decreased from T2-T4, and then returned to baseline by T6. Significant time effects were observed for plasma SOD (p < 0.0001) and IL-6 (p < 0.0001), and muscle expression of IL-6 (p < 0.01) and IL-1β (p<0.01). Despite good dietary compliance, overall results from our study do not support the notion that four weeks of daily soy milk ingestion can attenuate systemic or local elevations in markers of oxidative stress or inflammation. However, data do suggest that the downhill running protocol utilized in this study can be effective at altering systemic and local markers of inflammation, and that ingestion of soy may help to maintain plasma TNF-α levels even when exposed to a stress inducing stimulus, although more data exploring this conjecture is certainly warranted.Item An investigation of the effects of regular exercise in older males on oxidative stress, skeletal muscle apoptosis, and atrophy-related gene expression in response to muscle insult.(2009-08-24T20:26:00Z) Buford, Thomas Wayne.; Willoughby, Darryn Scott, 1963-; Health, Human Performance and Recreation.; Baylor University. Dept. of Health, Human Performance and Recreation.The purposes of the present study were to examine the role of physical activity in males between 55-75 years of age on skeletal muscle strength and biochemical pathways indicative of muscle atrophy before and after eccentric treadmill exercise. Twenty-seven apparently-healthy, non-smoking men (62.22±6.16 yr, 175.26±5.31 cm, 88.74±12.53 kg) participated in the study and were grouped at either physically-active (N=14, at least 15 hours of exercise per month) or sedentary (N=13, no regular exercise). Following a familiarization session, participants completed skeletal muscle performance testing as well as an eccentric treadmill protocol (-17.5% grade) consisting of three 15 minute sets at 75% of VO₂max. Participants donated venous blood prior to, immediately following, and 24h following exercise and a muscle biopsy sample prior to, 3h following, and 24h following exercise. Muscle performance was determined using a Biodex Isokinetic Dynamometer. Venous blood was analyzed for CK, LDH, cortisol, TNFα, IL1β, protein carbonyls, 8-isoprostane, and total antioxidant activity. Skeletal muscle tissue samples were analyzed for mRNA expression of atrophy-related genes (Atrogin1, MURF1, FOXO1, FOXO3, IKKB, Ubiquitin, Ubiqutin E2, HSP27, HSP72, Id1, Id2, Id3, Myostatin, 20S C2, 20S C3, Calpain1, and Calpain2), protein content of pIKBα, Caspase3, Bax, and Bcl2, and DNA binding activity of p53, NFkB p50, NFkB p65, and GC receptor. At baseline, significant differences existed between groups for body weight (p=0.047), VO₂max (p<0.001), % body fat (p<0.001), SBP (p=0.032), mRNA expression of FOXO1 (p=0.043), protein content of Bax (p = 0.015), and several muscular performance variables. Following exercise, significant group x time interactions were observed for cortisol (p=0.048), FOXO1 (p=0.001), IKKB (p=0.013), and ID1 (p=0.049), while a number of group differences were observed for individual time points that indicate improved muscular aging in the physically-active group. The results of the present study indicate that regular physical activity in advanced age attenuates eccentric exercise-induced muscle force decrements. Meanwhile, sedentary individuals appear to exhibit altered muscular signaling in an apparently unsuccessful attempt to preserve muscle mass and force production.