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Muscle fiber type-specific response of Hsp70 expression in human quadriceps following acute isometric exercise.
J Appl Physiol (1985). 2007 Dec; 103(6):2105-11.JA

Abstract

To investigate the time course of fiber type-specific heat shock protein 70 (Hsp70) expression in human skeletal muscle after acute exercise, 10 untrained male volunteers performed single-legged isometric knee extensor exercise at 60% of their maximal voluntary contraction (MVC) with a 50% duty cycle (5-s contraction and 5-s relaxation) for 30 min. Muscle biopsies were collected from the vastus lateralis before (Pre) exercise in the rested control leg (C) and immediately after exercise (Post) in the exercised leg (E) only and on recovery days 1 (R1), 2 (R2), 3 (R3), and 6 (R6) from both legs. As demonstrated by Western blot analysis, whole muscle Hsp70 content was unchanged (P > 0.05) immediately after exercise (Pre vs. Post), was increased (P < 0.05) by approximately 43% at R1, and remained elevated throughout the entire recovery period in E only. Hsp70 expression was also assessed in individual muscle fiber types I, IIA, and IIAX/IIX by immunohistochemistry. There were no fiber type differences (P > 0.05) in basal Hsp70 expression. Immediately after exercise, Hsp70 expression was increased (P < 0.05) in type I fibers by approximately 87% but was unchanged (P > 0.05) in type II fibers (Pre vs. Post). At R1 and throughout recovery, Hsp70 content in E was increased above basal levels (P < 0.05) in all fiber types, but Hsp70 expression was always highest (P < 0.05) in type I fibers. Hsp70 content in C was not different from Pre at any time throughout recovery. Glycogen depletion was observed at Post in all type II, but not type I, fibers, suggesting that the fiber type differences in exercise-induced Hsp70 expression were not related to glycogen availability. These results demonstrate that the time course of exercise-induced Hsp70 expression in human skeletal muscle is fiber type specific.

Authors+Show Affiliations

Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada. rtupling@uwaterloo.caNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

17916670

Citation

Tupling, A R., et al. "Muscle Fiber Type-specific Response of Hsp70 Expression in Human Quadriceps Following Acute Isometric Exercise." Journal of Applied Physiology (Bethesda, Md. : 1985), vol. 103, no. 6, 2007, pp. 2105-11.
Tupling AR, Bombardier E, Stewart RD, et al. Muscle fiber type-specific response of Hsp70 expression in human quadriceps following acute isometric exercise. J Appl Physiol (1985). 2007;103(6):2105-11.
Tupling, A. R., Bombardier, E., Stewart, R. D., Vigna, C., & Aqui, A. E. (2007). Muscle fiber type-specific response of Hsp70 expression in human quadriceps following acute isometric exercise. Journal of Applied Physiology (Bethesda, Md. : 1985), 103(6), 2105-11.
Tupling AR, et al. Muscle Fiber Type-specific Response of Hsp70 Expression in Human Quadriceps Following Acute Isometric Exercise. J Appl Physiol (1985). 2007;103(6):2105-11. PubMed PMID: 17916670.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Muscle fiber type-specific response of Hsp70 expression in human quadriceps following acute isometric exercise. AU - Tupling,A R, AU - Bombardier,E, AU - Stewart,R D, AU - Vigna,C, AU - Aqui,A E, Y1 - 2007/10/04/ PY - 2007/10/6/pubmed PY - 2008/2/22/medline PY - 2007/10/6/entrez SP - 2105 EP - 11 JF - Journal of applied physiology (Bethesda, Md. : 1985) JO - J Appl Physiol (1985) VL - 103 IS - 6 N2 - To investigate the time course of fiber type-specific heat shock protein 70 (Hsp70) expression in human skeletal muscle after acute exercise, 10 untrained male volunteers performed single-legged isometric knee extensor exercise at 60% of their maximal voluntary contraction (MVC) with a 50% duty cycle (5-s contraction and 5-s relaxation) for 30 min. Muscle biopsies were collected from the vastus lateralis before (Pre) exercise in the rested control leg (C) and immediately after exercise (Post) in the exercised leg (E) only and on recovery days 1 (R1), 2 (R2), 3 (R3), and 6 (R6) from both legs. As demonstrated by Western blot analysis, whole muscle Hsp70 content was unchanged (P > 0.05) immediately after exercise (Pre vs. Post), was increased (P < 0.05) by approximately 43% at R1, and remained elevated throughout the entire recovery period in E only. Hsp70 expression was also assessed in individual muscle fiber types I, IIA, and IIAX/IIX by immunohistochemistry. There were no fiber type differences (P > 0.05) in basal Hsp70 expression. Immediately after exercise, Hsp70 expression was increased (P < 0.05) in type I fibers by approximately 87% but was unchanged (P > 0.05) in type II fibers (Pre vs. Post). At R1 and throughout recovery, Hsp70 content in E was increased above basal levels (P < 0.05) in all fiber types, but Hsp70 expression was always highest (P < 0.05) in type I fibers. Hsp70 content in C was not different from Pre at any time throughout recovery. Glycogen depletion was observed at Post in all type II, but not type I, fibers, suggesting that the fiber type differences in exercise-induced Hsp70 expression were not related to glycogen availability. These results demonstrate that the time course of exercise-induced Hsp70 expression in human skeletal muscle is fiber type specific. SN - 8750-7587 UR - https://www.unboundmedicine.com/medline/citation/17916670/Muscle_fiber_type_specific_response_of_Hsp70_expression_in_human_quadriceps_following_acute_isometric_exercise_ L2 - https://journals.physiology.org/doi/10.1152/japplphysiol.00771.2007?url_ver=Z39.88-2003&amp;rfr_id=ori:rid:crossref.org&amp;rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -