28069800

28069800 - SHORT COMMUNICATION Anticipation of subsequent...

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Unformatted text preview: SHORT COMMUNICATION Anticipation of subsequent demanding exercise increases the expression of haem oxygenase-1 mRNA in human lymphocytes DANIELLA MARKOVITCH 1 , REX M. TYRRELL 2 & DYLAN THOMPSON 1 1 Sport and Exercise Science, School for Health, University of Bath, Bath BA2 7AY, UK, and 2 Department of Pharmacy and Pharmacology, University of Bath, Bath BA2 7AY, UK (Received 21 December 2006; revised 9 March 2007; accepted 24 March 2007) Abstract Oxidative stress induces the expression of the cytoprotective and anti-inflammatory protein haem oxygenase-1 (HO-1). In the present investigation, we show that anticipation of subsequent exercise elevates the expression of HO-1 mRNA in lymphocytes. A between-groups comparison of HO-1 mRNA expression in subjects about to complete a half marathon race vs. subjects who were asked to sit quietly in the laboratory showed an elevated expression of HO-1 mRNA prior to exercise (2.6-fold higher in subjects prior to the half marathon, P , 0.01). This observation led us to examine whether anticipation of subsequent exercise leads to differences in lymphocyte HO-1 mRNA expression within the same subjects. In a second experiment, the same individuals completed two trials, one exercise and one rest, approximately 2 weeks apart in a randomised cross-over design. Lymphocyte HO-1 mRNA expression was greater prior to exercise (1.4 ^ 0.3-fold higher in the exercise trial, P , 0.05). These results suggest that knowledge of subsequent demanding exercise may lead to an anticipatory induction of HO-1 mRNA. We tentatively propose that this process has evolved to prepare lymphocytes for subsequent exercise-induced oxidative stress although the mechanism remains to be elucidated. Keywords: Cortisol, free radicals, gene expression, lightcycler, oxidative stress Introduction Haem oxygenase-1 (HO-1) induction is a general response to oxidative stress (Keyse and Tyrrell 1989). The expression of HO-1 protein is controlled at the level of transcription (Keyse et al. 1990). HO-1 mRNA accumulates in many tissues and species and it has been proposed that HO-1 mRNA expression may be a useful marker of cellular oxidative stress (Tyrrell and Basu-Modak 1994). Several studies have shown that lymphocytes have the ability to up-regulate HO-1 in response to oxidative stress. For example, H 2 O 2 treatment, hyperbaric oxygen exposure, exercise and heavy metals all induce lymphocyte HO-1 (Ryter et al. 2006). Several investigations have reported that prior up-regulation of HO-1 provides enhanced protection to cells exposed to a subsequent source of oxidative stress (Vile et al. 1994; Rothfuss et al. 2001; McArdle et al. 2004). Anxiety is known to induce oxidative stress (Irie et al. 2001; Sivonova et al. 2004; Hovatta et al. 2005) and our preliminary unpublished observations indicated that knowledge of participation in subsequent demanding exercise increases the expression of HO-1 mRNA in lymphocytes. In order to test this hypothesis, we conducted two independent...
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28069800 - SHORT COMMUNICATION Anticipation of subsequent...

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