The influence of hyperbaric environment on the skeletal muscle mitochondrial energetic of rats after induced muscle contusion

Objective: Analyze the influence of the hyperbaric environment on skeletal muscle mitochondrial bioenergetic end-points of rats submitted to muscle contusion. Methods: Twelve female Wistar rats were randomly assigned to three groups. All rats were submitted to muscle contusion in the right gastrocnemius through a standard protocol. The control group (C) remained under normo- baric conditions without any treatment. The hyperbaric air (HB) and the hyperbaric oxygen (HBO2) groups had four sessions of HBO2 therapy 60 minutes, six, 12, 24 and 48 hours after the injury at 253.25 kPa (2.5 atmospheres absolute/ATA) with air or 100% oxygen, respectively. The animals were sacrificed 48 hours after muscle injury, and both muscles (injured and non-injured) were analyzed. Muscle mitochondrial bioenergetics and mitochondrial permeability transition pore (MPTP) susceptibility were evaluated. Results: Significant differences were found in all parameters between the injured and the non-injured gastrocnemius in the C group. In the HB group, significantly better results concerning bioenergetics-related end points with complex I and II substrates where found in the right gastrocnemius, whereas in the HBO2 group the time to Vmax (time that elapsed until the faster swelling kinetics starts) was significantly higher and the swelling amplitude was significantly smaller than in other groups, which suggest a lower susceptibility to MPTP opening. Conclusion: The present data suggest that hyperbaric exposure, particularly with oxygen, positively modulates the efficiency of skeletal muscle mitochondria after muscle contusion.