| Autor: |
Rezende RM; Department of Physiotherapy, Universidade Federal de Juiz de Fora, Governador Valadares 35020-360, MG, Brazil., Coimbra RS; Instituto Rene Rachou-Fiocurz Minas, Belo Horizonte 30190-009, MG, Brazil., Kohlhoff M; Instituto Rene Rachou-Fiocurz Minas, Belo Horizonte 30190-009, MG, Brazil., Favarato LSC; Department of Veterinary Medicine, Universidade Federal de Viçosa, Viçosa 36570-900, MG, Brazil., Martino HSD; Department of Nutrition and Health, Universidade Federal de Viçosa, Viçosa 36570-900, MG, Brazil., Leite LB; Exercise Biology Laboratory, Department of Physical Education, Universidade Federal de Viçosa, Viçosa 36570-900, MG, Brazil.; Department of Sports Sciences, Instituto Politécnico de Bragança, 5300-253 Bragança, Portugal., Soares LL; Exercise Biology Laboratory, Department of Physical Education, Universidade Federal de Viçosa, Viçosa 36570-900, MG, Brazil., Encarnação S; Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal.; Department of Physical Education, Sport and Human Movement, Universidad Autónoma de Madrid, 28049 Madrid, Spain.; Research Centre for Active Living and Wellbeing (Livewell), Instituto Politécnico de Bragança, 5300-253 Bragança, Portugal., Forte P; Department of Sports Sciences, Instituto Politécnico de Bragança, 5300-253 Bragança, Portugal.; Research Centre for Active Living and Wellbeing (Livewell), Instituto Politécnico de Bragança, 5300-253 Bragança, Portugal.; CI-ISCE, Instituto Superior de Ciências Educativas do Douro (ISCE Douro), 4560-547 Penafiel, Portugal.; Research Centre in Sports Sciences, Health Sciences and Human Development, 5001-801 Vila Real, Portugal., de Barros Monteiro AM; Department of Sports Sciences, Instituto Politécnico de Bragança, 5300-253 Bragança, Portugal.; Research Centre for Active Living and Wellbeing (Livewell), Instituto Politécnico de Bragança, 5300-253 Bragança, Portugal., Peluzio MDCG; Department of Nutrition and Health, Universidade Federal de Viçosa, Viçosa 36570-900, MG, Brazil., José Natali A; Exercise Biology Laboratory, Department of Physical Education, Universidade Federal de Viçosa, Viçosa 36570-900, MG, Brazil. |
| Abstrakt: |
Though the mechanisms are not fully understood, tryptophan (Trp) and physical exercise seem to regulate mechanical hypersensitivity in fibromyalgia. Here, we tested the impact of Trp supplementation and continuous low-intensity aerobic exercise on the modulation of mechanical hypersensitivity in a fibromyalgia-like model induced by acid saline in female rats. Twelve-month-old female Wistar rats were randomly divided into groups: [control (n = 6); acid saline (n = 6); acid saline + exercise (n = 6); acid saline + Trp (n = 6); and acid saline + exercise + Trp (n = 6)]. Hypersensitivity was caused using two intramuscular jabs of acid saline (20 μL; pH 4.0; right gastrocnemius), 3 days apart. The tryptophan-supplemented diet contained 7.6 g/hg of Trp. The three-week exercise consisted of progressive (30-45 min) treadmill running at 50 to 60% intensity, five times (Monday to Friday) per week. We found that acid saline induced contralateral mechanical hypersensitivity without changing the levels of Trp, serotonin (5-HT), and kynurenine (KYN) in the brain. Hypersensitivity was reduced by exercise (~150%), Trp (~67%), and its combination (~160%). The Trp supplementation increased the levels of Trp and KYN in the brain, and the activity of indoleamine 2,3-dioxygenase (IDO), and decreased the ratio 5-HT:KYN. Exercise did not impact the assessed metabolites. Combining the treatments reduced neither hypersensitivity nor the levels of serotonin and Trp in the brain. In conclusion, mechanical hypersensitivity induced by acid saline in a fibromyalgia-like model in female rats is modulated by Trp supplementation, which increases IDO activity and leads to improved Trp metabolism via the KYN pathway. In contrast, physical exercise does not affect mechanical hypersensitivity through brain Trp metabolism via either the KYN or serotonin pathways. Because this is a short study, generalizing its findings warrants caution. |
