HSP70 induction during exercise and heat stress in rats: role of internal temperature

Abstract

The purpose of this study was to determine if the accumulation of the 72-kDa heat shock protein (HSP70) is elevated in response to a prolonged bout of submaximal exercise in which colonic temperature (Tco) remained at control levels. Sprague-Dawley rats were randomly assigned to one of four testing groups [n = 8 per group; ambient temperatures (Ta) for each condition are included]: 1) control (cool/rest; Ta = 24 degrees C); 2) cool and exercise (cool/exercise; Ta = 14 degrees C); 3) nonexertional heating (heat/rest; Ta = 42 degrees C); 4) heat and exercise (heat/exercise; Ta = 32 degrees C). All interventions were approximately 60 min in duration. An exercise bout consisted of treadmill running at 17 m/min and 0% grade, while the heat/rest and heat/exercise experiments consisted of heat exposure that was terminated when Tco reached 41 degrees C. Baseline Tco was similar for all four groups. In the cool/rest and cool/exercise groups, final Tco was not different from the baseline values, nor was it different between these two groups. In the heat/rest and heat/exercise groups, heating rates were similar. Tissue samples were obtained from the gastrocnemius, soleus, and extensor digitorum longus (EDL) muscles of the left hindlimb and the left ventricle 30 min after a trial was completed. An enzyme-linked immunosorbent assay specific for HSP70 was used to directly quantitate absolute levels of HSP70 in tissues. There were significant main effects of both heating and exercise for HSP70 levels in the gastrocnemius, soleus, and left ventricle (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Fatiguing stimulation of one skeletal muscle triggers heat shock proteins activation in several rat organs: the role of muscle innervation

“…As in previous rat (Skidmore et al, 1995) and human studies (Bai et al, 2002;Huang et al, 2007;Matt et al, 2007), we used ELISA kits to measure the phosphorylated HSP contents in tissues. Our study was complemented by measuring the changes in nonphosphorylated HSP content using western blotting.…”

“…We did not find data in the literature on simultaneous measurement of phosphorylated and nonphosphorylated HSPs in muscles. Indeed, most previous studies used western blotting to measure the HSP content in muscle biopsies and reported a significant HSP70 elevation in working muscle 20min (Locke et al, 1990) and 30min (Skidmore et al, 1995) after a treadmill bout in rats and 30min after an eccentric exercise in humans (Paulsen et al, 2007). ELISA measurements of plasma HSP27 and HSP70 content were performed in healthy humans and reported an early elevation of the phosphorylated HSP27 10min after maximal static handgrip (Brerro-Saby et al, 2010) and maximal cycling exercise ) while the phosphorylated HSP70 response began at 60min .…”

“…The exercise-induced expression of heat shock proteins (HSPs) in skeletal muscle is well documented in rodents (Huey et al, 2010;Locke et al, 1990;McArdle et al, 2001;Skidmore et al, 1995) and also humans (Morton et al, 2006;Paulsen et al, 2007;Tupling et al, 2007). Plasma HSP levels also increase after static (BrerroSaby et al, 2010) and dynamic exercise ) in healthy subjects.…”

Heat shock response and autophagy—cooperation and control

“…25,132 HSP70 is the most highly conserved member in the HSP family and has been studied in the response to acute exercise or exercise training in animals. Brief (5 min) eccentric exercise produces no increase in HSP70 protein expression in the muscle tissue, 133 but longer and more exhaustive treadmill running 134,135 or eccentric exercise 136,137 results in a significant increase in HSP70 protein expression in cardiac and skeletal muscles. Elevated HSP70 levels are also observed in lung and kidney in response to strenuous endurance exercise.…”

Rapid upregulation of GLUT-4 and MCT-4 expression during 16 h of heavy intermittent cycle exercise

“…The increase in strain occurring as a result of the intermittent exercise protocol can be appreciated by the early increase in HSP70 that also occurs. The increase in HSP70 is known to respond to a variety of perturbations, including exercise (40,41,56). The increase in HSP70 is also known to be involved in the protection of a range of proteins involved in such things as mitochondrial function (55) and sarcoplasmic reticulum Ca 2ϩ cycling (59).…”