Treadmill Training Increases SIRT-1 and PGC-1αProtein Levels and AMPK Phosphorylation in Quadriceps of Middle-Aged Rats in an Intensity-Dependent Manner

Abstract

The present study investigated the effects of running at 0.8 or 1.2 km/h on inflammatory proteins (i.e., protein levels of TNF-α, IL-1β, and NF-κB) and metabolic proteins (i.e., protein levels of SIRT-1 and PGC-1α, and AMPK phosphorylation) in quadriceps of rats. Male Wistar rats at 3 (young) and 18 months (middle-aged rats) of age were divided into nonexercised (NE) and exercised at 0.8 or 1.2 km/h. The rats were trained on treadmill, 50 min per day, 5 days per week, during 8 weeks. Forty-eight hours after the last training session, muscles were removed, homogenized, and analyzed using biochemical and western blot techniques. Our results showed that: (a) running at 0.8 km/h decreased the inflammatory proteins and increased the metabolic proteins compared with NE rats; (b) these responses were lower for the inflammatory proteins and higher for the metabolic proteins in young rats compared with middle-aged rats; (c) running at 1.2 km/h decreased the inflammatory proteins and increased the metabolic proteins compared with 0.8 km/h; (d) these responses were similar between young and middle-aged rats when trained at 1.2 km. In summary, the age-related increases in inflammatory proteins, and the age-related declines in metabolic proteins can be reversed and largely improved by treadmill training.

Voluntary Running Attenuates Metabolic Dysfunction in Ovariectomized Low-Fit Rats

“…HCR rats responded to EX with a greater increase in activation site of pAMPK, likely due to the fact that wheel running volume was 5-fold greater in HCR than LCR rats. Another study (22) demonstrated that treadmill-trained rats at 1.2 km/h displayed greater AMPK phosphorylation compared to rats trained at 0.8 km/h suggesting that the difference between the HCR and LCR rats studied here may have been attributed to a higher exercise intensity in HCR. Unfortunately, exercise intensity was not monitored in the present study; future studies should address this question of whether different exercise intensities determine degree of AMPK activation.…”

Fructose Consumption in the Development of Obesity and the Effects of Different Protocols of Physical Exercise on the Hepatic Metabolism

“…It is suggested that this effect may be caused by the fact that aerobic exercise reduces the levels and activity of pro-inflammatory proteins [82,83], and protein-tyrosine phosphatase 1B (PTP-1B), thereby reducing the insulin resistance state [82]. Therefore, aerobic exercise increases both insulin action in skeletal muscle and glucose uptake by mechanisms that are independent of the action of this hormone.…”

“…Finally, it has also been demonstrated in humans that the activation of proteins involved in protein synthesis, such as the mechanistic target of rapamycin (mTOR) and ribosomal protein S6 kinase beta-1 (S6K1), are not compromised. In fact, AMPK activation [125], a protein that has an increased activity caused by the increase in AMP levels provided by aerobic exercise [83,126], was shown to be able to negatively influence the stimulation of protein synthesis by inhibiting the mTOR pathway in rodents [127]. From this, many other studies have been conducted to better understand the changes promoted by this new and promising exercise protocol, in many different contexts, because it is believed that this type of exercise can activate different pathways and promote several improvements.…”

Training for skeletal muscle capillarization: a Janus-faced role of exercise intensity?

“…Moreover, peroxisome proliferator-activated γ-receptor co-activator (PGC-1α), an important regulator of both angiogenesis and mitochondrial biogenesis, was also increased to the same extent in the two training protocols. These findings are interesting, because activation of PGC-1α and subsequent mitochondrial biogenesis is largely intensity dependent (Oliveira et al 2014), whereas angiogenesis appears to be hampered when intensity gets too high (Høier et al 2013). As such, recent reports have shown that increasing the number of all-out efforts while reducing total training volume has a negative impact on skeletal muscle VEGF levels and ultimately capillarization (Gliemann et al 2015).…”