Effects of RRR-α-Tocopherol on Leukocyte Expression of HSP72 in Response to Exhaustive Treadmill Exercise

Abstract

Previous research revealed an increased expression of HSP72 in leukocytes after vigorous endurance exercise. We questioned whether more intensive but shorter exercise also induces leukocyte HSP72 synthesis. To delineate the role of reactive oxygen species (ROS) in exercise-related HSP72 induction, we additionally examined the effect of RRR-alpha-tocopherol (alpha-toc) on HSP72 expression using a double-blind placebo (P) controlled cross-over design. After supplementation with alpha-toc (500 I.U. daily) or P for 8 days, 9 male subjects performed a combined exhaustive treadmill protocol (total duration 29.4 +/- 2.0 min). HSP72 was assessed on mRNA (RT-PCR) and protein levels (flow cytometry). HSP72 mRNA rose 3 h after exercise only in the P group, but individual differences (alpha-toc - P) did not reveal significant treatment effects. A moderate but significant rise of HSP72 protein occurred in granulocytes up to 48 h after exercise. Three hours post-exercise, granulocyte HSP72 protein was lower when subjects received alpha-toc, but this effect vanished 24 and 48 h post-exercise. Exhaustive treadmill exercise augments HSP72 mRNA in leukocytes and induced a moderate but prolonged response of granulocyte HSP72 protein. These exercise effects are lower when compared to earlier findings obtained after vigorous endurance exercise. ROS seem to be involved, but do not play the major role in the induction of granulocyte HSP72 synthesis after exhaustive exercise.

Stress Proteins and Heat Shock Proteins

“…In the other experimental group of the same study, antioxidant co-supplementation with ascorbic acid and α-tocopherol (an isoform of vitamin E) gave a similar pattern of HSP72 mRNA expression and protein content both in skeletal muscle and plasma, although these changes were not statistically significant [92]. Consistent with this study, in an early investigation, exhaustive treadmill running induced leukocyte HSP72 mRNA expression and significantly increased granulocyte HSP72 protein levels only in the placebo group, but not in a supplementation group which received 500 IU daily of α-tocopherol for 8 days [93]. Consistent with this study, in an early investigation, exhaustive treadmill running induced leukocyte HSP72 mRNA expression and significantly increased granulocyte HSP72 protein levels only in the placebo group, but not in a supplementation group which received 500 IU daily of α-tocopherol for 8 days [93].…”

Heat shock response and autophagy—cooperation and control

“…145 On the contrary, running in a hot environment (40 C) with body temperature exceeding 39 C results in a significant increase in HSP70 in PBMCs within 1 h after exercise 146 following an increase in HSP70 gene 147 and transcript expression. 148,149 Exhaustive endurance exercise has been consistently shown to trigger heat stress response in human leukocytes. In subjects who completed a half marathon (21.1 km) with an increased plasma creatine kinase activity indicating exercise-induced skeletal muscle damage and rectal temperature reaching 44 C, there is a post-exercise increase in HSP70 protein expression in monocytes and granulocytes that remains elevated for up to 1 d post-exercise.…”

Thermotolerance and heat acclimation may share a common mechanism in humans

“…While quercetin's antioxidant capacity may have reduced cellular stress, and thus the impetus for activation of the heat shock response, it is also tenable that quercetin's antioxidant properties may have repressed formation of reactive oxygen species, which are integral mediators of cellular signaling responses. Although these effects have not been attributed to quercetin in a human model, suppressed leukocyte expression of HSF-1 and HSP70 following exhaustive treadmill exercise was shown in humans supplemented with ␣-tocopherol, a similar antioxidant (19,55). More recently, oral antioxidant supplementation has been reported to suppress the improvements in insulin sensitivity that are normally associated with combined endurance/resistance exercise (59).…”