Sickle cell disease (SCD) is associated with an impaired oxygen delivery to skeletal muscle that could alter ATP production processes. The present study aimed to determine the effects of sickle hemoglobin (HbS) on muscle pH homeostasis in response to exercise in homozygous (HbSS, n = 9) and heterozygous (HbAS, n = 10) SCD (Townes) mice in comparison to control (HbAA, n = 10) littermates. Magnetic resonance spectroscopy of phosphorus 31 enabled to measure intramuscular pH (pHi) and phosphocreatine (PCr) concentration during rest-stimulation-recovery protocols at two different intensities. Maximal activity of some enzymes involved in muscle energetics and content of proteins involved in pH regulation were also investigated. HbSS mice presented a more pronounced exercise-induced intramuscular acidosis, whatever the intensity of exercise. Moreover, the depletion of PCr was also exacerbated in HbSS mice in response to intense exercise as compared to both HbAA and HbAS mice (p < 0.01). While no difference was observed concerning proteins involved in muscle pH regulation, the activity of enolase (a glycolytic enzyme) was higher in both HbSS and HbAS mice as compared to controls (p < 0.05). Interestingly, HbAS mice presented also metabolic impairments as compared to their control counterparts. This study has identified for the first time an exacerbated exercise-induced intramuscular acidosis in SCD mice.
- hemoglobin polymerization
- exercise intensity
- muscle energetics
- physical activity
- Copyright © 2016, Journal of Applied Physiology