Resistance exercise-induced apoptosis response to short-term creatine supplementation in middle-aged men Running title: creatine supplementation and apoptosis

Background: Creatine (Cr) as an ergogenic aid for improving health and sports performance is recently researched in attenuating stress-induced apoptosis. No studies to date address the effect of Cr supplementation on systemic apoptosis to acute resistance exercise. Objective: The purpose of this study was to determine the short-term (one week) effects of oral Cr supplementation on apoptosis markers at strenuous acute exercise in middle-aged men. Methods: In a placebo-controlled, double-blind, randomized, parallel study, twenty men (۴۵.۵۹ ± ۵.۴۳ years; ۷۷.۴۵ ± ۶.۶۵ kg; ۱۷۳.۰۵ ± ۳.۴۸ cm) were randomly assigned to supplement with ۲۰ g per day of Cr monohydrate (n=۱۰) or placebo (maltodextrin, n=۱۰) for a week. On ۸th day, subjects performed an acute resistance exercise with ۸۰% ۱RM. Blood samples were taken on day prior to supplementation loading and immediately after acute exercise for the measurement of the serum caspase-۳, -۹ and -۱۲ concentrations. Results: After acute exercise, caspase-۳ (۴۱.۲۶%, p<۰.۰۰۱), -۹ (۳۸.۰۱%, p=۰.۰۰۳) and -۱۲ (۵۷.۰۲%, p=۰.۰۳۰) levels significantly increased in the placebo group compared to pre supplementation. In contrast, serum level caspases slightly but not significantly increased in the Cr group (p>۰.۰۵). Conclusions: Our results indicated that short-term Cr supplementation prevented exercise-induced apoptosis in middle-aged men, which was confirmed by attenuated caspase-۳, -۹ and -۱۲ in the Cr group. Thus, ۷ days Cr supplementation may be a useful strategy for preventing apoptosis by intensive acute exercise.

Keywords:

Creatine loading , caspases , one bout exercise , programmed cell death