Ibuprofen, Flurbiprofen or Naproxen Sodium Minimally Influences Musculoskeletal Adaptations to Treadmill Exercise in Rats.

BACKGROUND: Non-steroidal anti-inflammatory drugs (NSAIDs) may influence musculoskeletal health. The purpose of this study was to compare the effects of three different NSAIDS: naproxen sodium, ibuprofen, flurbiprofen or a placebo on musculoskeletal adaptations in rodents with or without 6 weeks of aerobic exercise. METHODS: Nine-week-old male Wistar rats (n = 80) were randomized to either exercise (EX) or no-exercise control (CON) conditions and treated with naproxen, ibuprofen (IBU), flurbiprofen (FLU) or placebo (PLA). For exercise, rats ran 5 days per week for 6 weeks at a 5% incline on a motorized treadmill for 30 min. Three-point bending (3 PB) and microcomputed tomography (microCT) were measured in the femur. Anabolic muscle signalling pathways were measured in the quadriceps. Muscle fibre cross-sectional area (CSA) and fibre type were measured in the soleus. Data were analysed using a two-way ANOVA for treatment by condition and is visualized as mean ± standard deviation. RESULTS: For 3 PB, there was an exercise effect for ultimate bending energy, postyield energy, toughness, postyield toughness, postyield displacement, ultimate strain and postyield strain (all, p < 0.05). There was a treatment by condition effect for Young's Modulus, where placebo exercise was less than placebo control (PLA EX: 3256.44 ± 463.41 MPa, PLA CON: 4849.94 ± 836.70 MPa, p < 0.05). For microCT, there was a treatment by condition effect for trabecular thickness (p = 0.047) and the IBU EX group increased thickness compared with the IBU CON group (IBU EX: 0.133 ± 0.011 mm, IBU CON: 0.121 ± 0.007 mm, p = 0.027). In the quadriceps, for myosin heavy chain abundance, there was a treatment by condition effect (p = 0.046) and ibuprofen exercise was lower than ibuprofen control (IBU EX: 0.636 ± 0.513 AU, IBU CON: 1.81 ± 1.012 AU, p = 0.016). There was no treatment by condition effect for phosphorylation of the AKT, AMPK or ERK pathways (all, p > 0.05). In the soleus, there was no treatment by condition effect for fibre type percentage or muscle CSA (p > 0.05). CONCLUSIONS: NSAIDs did not have a strong negative or positive effect on musculoskeletal adaptations to 6 weeks of treadmill running in young healthy male rodents.