Health, Exercise, and Sports Sciences ETDs

Trevor Gillum

Publication Date

9-9-2010

Abstract

This study evaluated possible sex differences in intracellular heat shock protein 72 (Hsp72), intracellular cytokines, and extracellular Hsp72 (eHsp72) before and after exercise in the heat. Nine non-heat acclimated women (W) (age 23 ± 3, BF 21 ± 2%, VO2max 58 ± 5 ml/kgFFM/min) and nine non-heat acclimated men (M) (age 25 ± 5, BF 12 ± 5%, VO2max 60 ± 7 ml/kgFFM/min) completed 2 treadmill bouts at 60% VO2max for 60 min in a 42°C, 20% RH environment. The W had normal menstrual cycles and were tested in counterbalanced order during follicular (fol) and luteal (lut) phases. M and Ws duplicate trials were separated by 12 ± 2 days. Blood samples were drawn pre, 0, 1, and 4 hrs post-exercise. Mononucleated cells were analyzed for Hsp72, IL-1ra, IL-6, and TNF-α using flow cytometry. eHsp72 was analyzed using ELISA. In trial 1, Hsp72 content increased in M by 37% 4 hrs post exercise (p<0.05), but did not change significantly in W at any time after exercise. When Hsp72 expression was normalized to baseline, M expressed greater Hsp72 than W (p<0.05) after exercise. Baseline Hsp72 increased by 26% in M from trial 1 to trial 2 (p<0.05), but this effect did not occur in W. eHsp72 did not change after exercise, but there was a main effect for M having higher levels than W (p<0.05). While cytokines did not change during exercise, W consistently expressed less IL-1ra than M (p<0.05). IL-6 and TNF-α were higher in the fol than lut phase at 4 hrs post exercise (p<0.05). Our findings suggest that unacclimated M and W differ in their expression of Hsp72 and eHsp72 after exercise in the heat. M up-regulate Hsp 72 after a single bout of exercise in the heat, which persisted for 12 days, suggesting an acquired cellular thermotolerance. The inhibition of Hsp72 expression in W after exercise could be due to a known effect of estrogen to stabilize the cell membrane or to its action as an anti-oxidant.'

Keywords

Exercise--Physiological aspects--Sex differences, Body temperature--Regulation--Sex differences, Heat shock proteins--Effect of heat on, Cytokines

Sponsors

Gatorade Sports Science Institute, University of New Mexico's Graduate Research and Development Grant

Document Type

Dissertation

Language

English

Degree Name

Physical Education, Sports and Exercise Science

Level of Degree

Doctoral

Department Name

Health, Exercise, and Sports Sciences

First Committee Member (Chair)

Kravitz, Len

Second Committee Member

Mermier, Christine

Third Committee Member

Moseley, Pope

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