We investigated the effects of different diets on adipose tissue, liver, serum morphology, and biomarkers in rats that voluntarily exercised. Male Sprague-Dawley rats (∼9–10 wk of age) exercised with resistance-loaded voluntary running wheels (EX; wheels loaded with 20–60% body mass) or remained sedentary (SED) over 6 wk. EX and SED rats were provided isocaloric amounts of either a ketogenic diet (KD; 20.2%-10.3%-69.5% protein-carbohydrate-fat), a Western diet (WD; 15.2%-42.7–42.0%), or standard chow (SC; 24.0%-58.0%-18.0%); n = 8–10 in each diet for SED and EX rats. Following the intervention, body mass and feed efficiency were lowest in KD rats, independent of exercise ( P < 0.05). Absolute and relative (body mass-adjusted) omental adipose tissue (OMAT) masses were greatest in WD rats ( P < 0.05), and OMAT adipocyte diameters were lowest in KD-fed rats ( P < 0.05). None of the assayed OMAT or subcutaneous (SQ) protein markers were affected by the diets [total acetyl coA carboxylase (ACC), CD36, and CEBPα or phosphorylated NF-κB/p65, AMPKα, and hormone-sensitive lipase (HSL)], although EX unexpectedly altered some OMAT markers (i.e., higher ACC and phosphorylated NF-κB/p65, and lower phosphorylated AMPKα and phosphorylated HSL). Liver triglycerides were greatest in WD rats ( P < 0.05), and liver phosphorylated NF-κB/p65 was lowest in KD rats ( P < 0.05). Serum insulin, glucose, triglycerides, and total cholesterol were greater in WD and/or SC rats compared with KD rats ( P < 0.05), and serum β-hydroxybutyrate was greater in KD vs. SC rats ( P < 0.05). In conclusion, KD rats presented a healthier metabolic profile, albeit the employed exercise protocol minimally impacts any potentiating effects that KD has on fat loss.

Purpose: Ketogenic diets (KD) can facilitate weight loss, but their effects on skeletal muscle remain equivocal. In this experiment we investigated the effects of two diets on skeletal muscle mitochondrial coupling, mitochondrial complex activity, markers of oxidative stress, and gene expression in sedentary and resistance exercised rats. Methods: Male Sprague-Dawley rats (9-10 weeks of age, 300-325 g) were fed isocaloric amounts of either a KD (17 g/day, 5.2 kcal/g, 20.2% protein, 10.3% CHO, 69.5% fat, n=16) or a Western diet (WD) (20 g/day, 4.5 kcal/g, 15.2% protein, 42.7% CHO, 42.0% fat, n=16) for 6 weeks. During these six weeks animals were either sedentary (SED, n=8 per diet group) or voluntarily exercised using resistance-loaded running wheels (EXE, n=8 per diet group). Gastrocnemius was excised and used for mitochondrial isolation and biochemical analyses. RESULTS: In the presence of a complex II substrate, the respiratory control ratio (RCR) of isolated gastrocnemius mitochondria was higher (p<0.05) in animals fed the KD compared to animals fed the WD. Complex I and IV enzyme activity was higher (p<0.05) in EXE animals regardless of diet. SOD2 protein levels and GLUT4 and PGC1α mRNA expression were higher (p<0.05) in EXE animals regardless of diet. CONCLUSION: Our data indicate that skeletal muscle mitochondrial coupling of complex II substrates is more efficient in chronically resistance trained rodents fed a KD. These findings may provide merit for further investigation, perhaps on humans.

This study investigated the effects of endurance exercise training on ileum antioxidant status, as well as tight junction, inflammatory, and nutrient transporter gene expression. Sprague–Dawley rats (4 month old) were assigned to sedentary (SED) or endurance exercise-training (EXE) groups (n = 8/group). EXE animals were trained on the treadmill for 10 days at a speed of 30 m/min at 0° incline for 60 min/day. SED and EXE animals were sacrificed (24 h after the final training bout) and the ileum was stored for analyses. The ileum of EXE had higher (p < 0.05) antioxidant protein levels of manganese superoxide dismutase and catalase compared to SED with no change (p > 0.05) in the lipid peroxidation biomarker 4-hydroxynonenal. Ileum mRNA expression of the tight junction gene zonulin increased (p < 0.05) and claudin 1 decreased (p < 0.05) in EXE compared to SED, but occludin and zonula occluden 1 were not different (p > 0.05) between SED and EXE. The ileum mRNA expressions of seven nutrient transporters (SLC5A8, SLC7A6, SLC6A19, SLC7A7, SLC27A2, SLC16A10, and SLC15A1) were not different between the two groups (p > 0.05). EXE had lower ileum TNFα mRNA expression (p < 0.05) compared to SED. No changes (p > 0.05) were found in the other inflammatory mRNAs including NFκB, IFNγ, IL6, CCL2, TLR4, and IL10. In addition, no changes in p-p65:p65 were detected. These findings suggest that 10 days of endurance exercise training up-regulates key endogenous antioxidant enzymes, decreases select inflammation markers, and alters select markers of tight junction permeability.

Amino acid supplementation has been shown to potentially reduced exercise-induced muscle soreness. Thus, the purpose of this study was to examine if branched chain amino acid and carbohydrate (BCAA...

Alterations in transcriptional and translational mechanisms occur during skeletal muscle aging and such changes may contribute to age-related atrophy. Herein, we examined markers related to global transcriptional output (i.e., myonuclear number, total mRNA and RNA pol II levels), translational efficiency [i.e., eukaryotic initiation and elongation factor levels and muscle protein synthesis (MPS) levels] and translational capacity (ribosome density) in the slow-twitch soleus and fast-twitch plantaris muscles of male Fischer 344 rats aged 3, 6, 12, 18 and 24 months (n=9-10 per group). We also examined alterations in markers of proteolysis and oxidative stress in these muscles (i.e., 20S proteasome activity, poly-ubiquinated protein levels and 4-HNE levels). Notable plantaris muscle observations included: a) fiber cross sectional area (CSA) was 59% (p<0.05) and 48% (p<0.05) greater in 12 month versus 3 month and 24 month rats, respectively, suggesting a peak lifetime value near 12 months and age-related atrophy by 24 months, b) MPS levels were greatest in 18 month rats (p<0.05) despite the onset of atrophy, c) while regulators of ribosome biogenesis [c-Myc and upstream binding factor (UBF) protein levels] generally increased with age, ribosome density linearly decreased from 3 months of age and RNA polymerase (Pol) I protein levels were lowest in 24 month old rats, and d) 20S proteasome activity was robustly up-regulated in 6 and 24 month rats (p<0.05). Notable soleus muscle observations included: a) fiber CSA was greatest in 6 month rats and was maintained in older age groups, and b) 20S proteasome activity was modestly but significantly greater in 24 month versus 3/12/18 month rats (p<0.05), and c) total mRNA levels (suggestive of transcriptional output) trended downward in older rats despite non-significant between-group differences in myonuclear number and/or RNA Pol II protein levels. Collectively, these findings suggest that plantaris, not soleus, atrophy occurs following 12 months of age in male Fisher rats and this may be due to translational deficits (i.e., changes in MPS and ribosome density) and/or increases in proteolysis rather than increased oxidative stress and/or alterations in global transcriptional mechanisms.

Background: We examined the acute effect of a red spinach extract (RSE) (1000 mg dose; ~90 mg nitrate (NO ${}_3^{-}$ )) on performance markers during graded exercise testing (GXT). Methods: For this randomized, double-blind, placebo (PBO)-controlled, crossover study, 15 recreationally-active participants (aged 23.1 ± 3.3 years; BMI: 27.2 ± 3.7 kg/m²) reported >2 h post-prandial and performed GXT 65–75 min post-RSE or PBO ingestion. Blood samples were collected at baseline (BL), pre-GXT (65–75 min post-ingestion; PRE), and immediately post-GXT (POST). GXT commenced with continuous analysis of expired gases. Results: Plasma concentrations of NO ${}_3^{-}$ increased PRE (+447 ± 294%; p < 0.001) and POST (+378 ± 179%; p < 0.001) GXT with RSE, but not with PBO (+3 ± 26%, −8 ± 24%, respectively; p > 0.05). No effect on circulating nitrite (NO ${}_2^{-}$ ) was observed with RSE (+3.3 ± 7.5%, +7.7 ± 11.8% PRE and POST, respectively; p > 0.05) or PBO (−0.5 ± 7.9%, −0.2 ± 8.1% PRE and POST, respectively; p > 0.05). When compared to PBO, there was a moderate effect of RSE on plasma NO ${}_2^{-}$ at PRE (g = 0.50 [−0.26, 1.24] and POST g = 0.71 [−0.05, 1.48]). During GXT, VO₂ at the ventilatory threshold was significantly higher with RSE compared to PBO (+6.1 ± 7.3%; p < 0.05), though time-to-exhaustion (−4.0 ± 7.7%; p > 0.05) and maximal aerobic power (i.e., VO₂ peak; −0.8 ± 5.6%; p > 0.05) were non-significantly lower with RSE. Conclusions: RSE as a nutritional supplement may elicit an ergogenic response by delaying the ventilatory threshold.