Treadmill training increases SIRT-1 and PGC-1 α protein 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-1 β , and NF- κ B) and metabolic proteins (i.e., protein levels of SIRT-1 and PGC-1 α , 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.

Figure 1

Effects of exercise protocols performed in different intensities on the TNF-α, IL-1 β, and NF-κB protein levels in the quadriceps of young and middle-aged rats. Protein levels of TNF-α (a), IL-1β (b), and NF-κB (c). Upper panels show representative blots of these proteins. Lower panels show representative blots of β-actin (a)–(c) protein levels. The results of scanning densitometry are expressed as arbitrary units. Bars represent means ± SEM of six rats. *P < 0.05 versus young NE rats, ^# P < 0.05 versus middle-aged NE rats, ^$ P < 0.05 versus young rats at 0.8 km/h, and ^& P < 0.05 versus middle-aged rats at 0.8 km/h.

Figure 2

Effects of exercise protocols performed in different intensities on the AMPK and ACC phosphorylation and SIRT-1 and PGC-1α protein levels in the quadriceps of young and middle-aged rats. Phosphorylation of the AMPK (a) and ACC (b) and protein levels of SIRT-1 (c) and PGC-1α (d). Upper panels show representative blots of these proteins. Lower panels show representative blots of total AMPK (a) and total ACC (b) protein levels. The results of scanning densitometry are expressed as arbitrary units. Bars represent means ± SEM of six rats. *P < 0.05 versus young NE rats, ^# P < 0.05 versus middle-aged NE rats, ^$ P < 0.05 versus young rats at 0.8 km/h, and ^& P < 0.05 versus middle-aged rats at 0.8 km/h.

Figure 3

Effects of exercise protocols performed in different intensities on the CPT1, Cyt-c, citrate synthase, and SDH protein levels and SDH and citrate synthase activity in the quadriceps of young and middle-aged rats. Protein levels of CPT1 (a), Cyt-c (b), SDH (c), and citrate synthase (e). Upper panels show representative blots of these proteins. The results of scanning densitometry are expressed as arbitrary units. The activities of succinate dehydrogenase (d) and citrate synthase (f) are expressed as nmol/min/mg of protein. Bars represent means ± SEM of six rats. *P < 0.05 versus young NE rats, ^# P < 0.05 versus middle-aged NE rats, ^$ P < 0.05 versus young rats at 0.8 km/h, and ^& P < 0.05 versus middle-aged rats at 0.8 km/h.

Figure 4

Effects of exercise protocols performed in different intensities on the complexes I, II, II-III, and IV activities in the quadriceps of young and middle-aged rats. Complexes I (a), II (b), II-III (c), and IV (d) activities are expressed as nmol/min/mg of protein. *P < 0.05 versus young NE rats, ^# P < 0.05 versus middle-aged NE rats, ^$ P < 0.05 versus young rats at 0.8 km/h, and ^& P < 0.05 versus middle-aged rats at 0.8 km/h.