Ibuprofen before Exercise Does Not Prevent Cortical Bone Adaptations to Training

Using a nonsteroidal anti-inflammatory drug (NSAID) before a single bout of mechanical loading can reduce bone formation response. It is unknown whether this translates to an attenuation of bone strength and structural adaptations to exercise training. Purpose: This study aimed to determine whether nonsteroidal anti-inflammatory drug use before exercise prevents increases in bone structure and strength in response to weight-bearing exercise. Methods: Adult female Wistar rats (n = 43) were randomized to ibuprofen (IBU) or vehicle (VEH) and exercise (EX) or sedentary (SED) groups in a 2 x 2 (drug and activity) ANCOVA design with body weight as the covariate, and data are reported as mean +/- SE. IBU drops (30 mgIkg(-1) BW) or VEH (volume equivalent) were administered orally 1 h before the bout of exercise. Treadmill running occurred 5 dIwk(-1) for 60 minId(-1) at 20 mImin(-1) with a 5-incline for 12 wk. Micro-CT, mechanical testing, and finite element modeling were used to quantify bone characteristics. Results: Drug-activity interactions were not significant. Exercise increased tibia cortical cross-sectional area (EX = 5.67 +/- 0.10, SED = 5.37 +/- 0.10 mm 2, P G 0.01) and structural estimates of bone strength (Imax: EX = 5.16 +/- 0.18, SED = 4.70 +/- 0.18 mm4, P G 0.01; SecModPolar: EX = 4.01 +/- 0.11, SED = 3.74 +/- 0.10 mm3, P < 0.01). EX had increased failure load (EX = 243 +/- 9, SED = 202 +/- 7 N, P G 0.05) and decreased distortion in response to a 200-N load (von Mises stress at tibia-fibula junction: EX = 48.2 +/- 1.3, SED = 51.7 +/- 1.2 MPa, P = 0.01). There was no effect of ibuprofen on any measurement tested. Femur results revealed similar patterns. Conclusion: Ibuprofen before exercise did not prevent the skeletal benefits of exercise in female rats. However, exercise that engenders higher bone strains may be required to detect an effect of ibuprofen.