Reduced catalase and increased hydrogen peroxide contribute to the protective effect of chronic exercise against microvascular dysfunction induced by acute exertion

Abstract

Previous studies indicate that hydrogen peroxide (H2O2) scavenger catalase (CAT) reduced the protective effect of chronic exercise against endothelial dysfunction after acute exertion. We hypothesized that: 1) CAT protein is reduced after a single weight lifting (WL) session and 2) CAT expression is reduced in resistance compared to aerobic trained athletes. Gluteal fat biopsies were obtained in healthy, sedentary (SED), conditioned (EX, runners>15 miles/wk or WL>3x/wk), before and after a progressive leg press WL session. Resistance arteries (RA) from biopsies were cannulated for vascular reactivity measurements in response to acetylcholine (ACh; 10−9-10−4M). H2O2 production and CAT protein were determined with DCF fluorescence and Western blot, respectively. All subjects had similar BP responses to WL. PEG-CAT reduced ACh dilation and H2O2 of EX subjects post- WL. CAT protein was reduced 45 ± 1% and 69 ± 1% in adipose and resistance arteries of EX subjects post- WL, respectively (n=12). The exercise-induced reduction in CAT protein was more pronounced in conditioned WL (61%; pre: 1.5 ± 0.2 vs. post: 0.6 ± 0.2) compared to runners (39%; pre: 1.5 ± 0.5 vs. post: 0.9 ± 0.3) and SED (26%; pre: 1.1 ± 0.2 vs. post: 0.8 ± 0.1). These data indicate that reduced CAT protein following acute exertion may rise more pronounced in RA of trained athletes compared to sedentary subjects. NIH (K23HL085614).