The Hsp72 and Hsp90α mRNA Responses to Hot Downhill Running Are Reduced Following a Prior Bout of Hot Downhill Running, and Occur Concurrently within Leukocytes and the Vastus Lateralis

Abstract

The leukocyte heat shock response (HSR) is used to determine individual's thermotolerance. The HSR and thermotolerance are enhanced following interventions such as preconditioning and/or acclimation/acclimatization. However, it is unclear whether the leukocyte HSR is an appropriate surrogate for the HSR in other tissues implicated within the pathophysiology of exertional heat illnesses (e.g., skeletal muscle), and whether an acute preconditioning strategy (e.g., downhill running) can improve subsequent thermotolerance. Physically active, non-heat acclimated participants were split into two groups to investigate the benefits of hot downhill running as preconditioning strategy. A hot preconditioning group (HPC; n = 6) completed two trials (HPC1HOTDOWN and HPC2HOTDOWN) of 30 min running at lactate threshold (LT) on −10% gradient in 30°C and 50% relative humidity (RH) separated by 7 d. A temperate preconditioning group (TPC; n = 5) completed 30 min running at LT on a −1% gradient in 20°C and 50% (TPC1TEMPFLAT) and 7 d later completed 30 min running at LT on −10% gradient in 30°C and 50% RH (TPC2HOTDOWN). Venous blood samples and muscle biopsies (vastus lateralis; VL) were obtained before, immediately after, 3, 24, and 48 h after each trial. Leukocyte and VL Hsp72, Hsp90α, and Grp78 mRNA relative expression was determined via RT-QPCR. Attenuated leukocyte and VL Hsp72 (2.8 to 1.8 fold and 5.9 to 2.4 fold; p < 0.05) and Hsp90α mRNA (2.9 to 2.4 fold and 5.2 to 2.4 fold; p < 0.05) responses accompanied reductions (p < 0.05) in physiological strain [exercising rectal temperature (−0.3°C) and perceived muscle soreness (~ −14%)] during HPC2HOTDOWN compared to HPC1HOTDOWN (i.e., a preconditioning effect). Both VL and leukocyte Hsp72 and Hsp90α mRNA increased (p < 0.05) simultaneously following downhill runs and demonstrated a strong relationship (p < 0.01) of similar magnitudes with one another. Hot downhill running is an effective preconditioning strategy which ameliorates physiological strain, soreness and Hsp72 and Hsp90α mRNA responses to a subsequent bout. Leukocyte and VL analyses are appropriate tissues to infer the extent to which the HSR has been augmented.

Acute and chronic effects of hot water immersion on inflammation and metabolism in sedentary, overweight adults

“…In the present study, participants' rectal temperature exceeded 38.5°C for~15 min only. This may also explain why an acute increase in iHsp72 following passive heating is a consistent finding in animal studies (28,64), but not in human studies (50), as the endogenous heat stress imposed in the former is much higher compared with the present and other studies in humans. Of note, the required heat stress might need to be even higher to induce acute increases in circulating eHsp72 concentrations (23).…”

Downhill Running: What Are The Effects and How Can We Adapt? A Narrative Review

“…Byrnes et al [ 193 ] reported smaller increases in plasma CK, plasma myoglobin and DOMS up to 48 h after a second DR bout when two 30 min bouts (slope: − 10%; intensity: 170 beats min −1 of heart rate recorded on level grade) were separated by 3-, 6- and 9-weeks. Further studies corroborated these results by reporting a lower leakage and/or a faster clearance of intracellular muscle proteins in the blood [ 46 , 63 , 67 , 85 , 92 , 121 , 141 , 143 , 165 , 181 , 185 ], lower DOMS [ 63 , 68 , 85 , 92 , 121 , 141 , 143 , 185 , 192 , 196 , 197 ] and enhanced recovery of MVC force/torque [ 63 ] after a second DR bout (Table 1 and Fig. 3 b).…”

“…3 a Schematic representation of the time course of alterations following downhill running (DR) and b current scientific evidence on the benefits of different adaptation strategies to DR (i.e. prior exposure to DR [ 46 , 63 , 67 , 68 , 85 , 92 , 121 , 141 , 143 , 165 , 181 , 184 , 185 , 192 , 193 , 196 , 197 ], preconditioning strategies [ 16 , 81 ], DR training [ 14 , 209 , 210 , 254 ], changes in stride pattern [ 32 , 67 , 68 , 218 , 219 , 221 , 220 , 228 , 255 ], the use of lower limb compression garments [ 15 , 236 , 237 ], and the use of specific footwear [ 28 , 149 , 253 , 256 ]. In a and b , orange, blue, red, purple, and green spheres correspond to isometric MVC force/torque loss, changes in running economy and mechanics, ultrastructural alterations, inflammation and oedema, and muscle soreness, respectively.…”

“…Bout 2 post 2 weeks + MVC torque decrement of KE + DOMS + Physiological strain (e.g. rectal temperature) during subsequent HS exercise + Perceived exertion and thermal sensation during subsequent HS exercise Tuttle et al [ 196 ] Physically active males ( n = 6) 30 min Lactate threshold (66% O 2max on average) − 10 Bout 1 and 2 in HS condition Bout 2 post 1 week + DOMS + Physiological strain (e.g. rectal temperature) + Cellular stress response and thermotolerance Preconditioning strategies Eston et al [ 16 ] Healthy male students ( n = 10) 5 × 8 min, r ’ = 2 min 80% HR max − 10 100 KE maximal eccentric contractions 2 weeks prior DR + Blood CK elevation + DOMS + MVC torque of KE (concentric and eccentric muscle actions) ↔ Muscle tenderness Lima et al [ 81 ] Young males ( n = 30) 30 min 70% O 2max (10.2 km h −1 on average) − 15 10 KE isometric MVCs 2-day prior DR + Faster recovery of KE MVC torque + DOMS + Blood CK elevation ↔ O 2 drift during DR and post RE changes (expressed as O 2 ) Downhill running training Schwane et al [ 14 ] Healthy adults ( n = 50; n = 20 in DR groups; 7 males and 13 females) 9 × 5 min, r ’ = 2 min 80% s O 2max recorded on level grade (9.4 km h −1 on average) − 10 5 sessions/week for 1 or 2 weeks + DOMS (especially with 2-weeks training) + Blood CK elevat...…”

Hypoxic Air Inhalation and Ischemia Interventions Both Elicit Preconditioning Which Attenuate Subsequent Cellular Stress In vivo Following Blood Flow Occlusion and Reperfusion

“…Amelioration of Hsp72 mRNA is not novel regarding efficacy of IPC to blunt the respective gene response post-reperfusion of occluded distal lower limb skeletal muscle (rat tibialis anterior) (Bushell et al, 2002a , b ) however, blunting of the Hsp72 mRNA stress response in vivo via HPC I within the presented paradigm is. It is ecologically relevant that the blunted response in HPC I is contained within a time frame whereby surgery may be performed i.e., up to 120PoTwith the time course of responses comparable to those observed in similar Hsp72 mRNA experiments (Febbraio et al, 2002 ; Tuttle et al, 2017 ). Mechanistically, this intervention mediated reduction in Hsp72 mRNA cannot be attributed to systemic reduction in OS (PC or GSH:GSSG; see Table 3 ) nor increased degradation of ROS-producing heme molecules by Hsp32 mRNA, as these outcome variables were unchanged within and between all conditions and time points (Table 3 , Figure 3 ).…”