Levels of biomarkers associated with subconcussive head hits in mixed martial arts fighters

Background Concussion and the damage resulting from this event related to brain function have been widely studied; however, little is known about subconcussive impacts, especially in Mixed Martial Arts (MMA) fighters, which is a combat and full contact sport in which most blows are aimed at the head. Objective This study aims to evaluate the biomarker levels associated with subconcussive hits to the head in MMA fighters. Methods This is an exploratory study in which 30 male subjects (10 MMA fighters, 10 healthy individuals who practice muscle training, and 10 healthy sedentary individuals) aged between 18 and 32 years (25.4 ± 3.8) were evaluated. These individuals underwent blood collection to assess their Ubiquitin C-terminal hydrolase (UCH-L1), Glial Fibrillary Acidic Protein (GFAP) and Brain Derived Neurotrophic Factor (BDNF) levels before, immediately after and 72 hours after the sparring session (for the fighters) and were compared between groups. Results Significant differences were found at baseline between active and healthy fighters in BDNF levels ( p = 0.03). A significant reduction of BDNF levels were also observed between the post-immediate and 72h after the sparring session ( p = 0.03). No differences were observed in the number or severity of symptoms reported by the fighters. Conclusion Despite the exploratory approach, the findings of this study may help to understand the influence of repeated subconcussive hits to the head in MMA fighters, as well as to propose preventive interventions which can minimize the effects of the impact of hits, preserving fighters’ neuronal integrity and function.