Hyperbaric oxygen reduces inflammation, oxygenates injured muscle, and regenerates skeletal muscle via macrophage and satellite cell activation

Kunikazu Tsuji,Naoki Yamamoto,Ichiro Sekiya,Masaki Horie,Takuya Oyaizu,Atsushi Okawa,Takeshi Muneta,Kazuyoshi Yagishita,Mitsuhiro Enomoto

doi:10.1038/s41598-018-19670-x

Kunikazu Tsuji, Naoki Yamamoto + Show 7 more

Open Access

https://doi.org/10.1038/s41598-018-19670-x

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Abstract

Hyperbaric oxygen treatment (HBO) promotes rapid recovery from soft tissue injuries. However, the healing mechanism is unclear. Here we assessed the effects of HBO on contused calf muscles in a rat skeletal muscle injury model. An experimental HBO chamber was developed and rats were treated with 100% oxygen, 2.5 atmospheres absolute for 2 h/day after injury. HBO reduced early lower limb volume and muscle wet weight in contused muscles, and promoted muscle isometric strength 7 days after injury. HBO suppressed the elevation of circulating macrophages in the acute phase and then accelerated macrophage invasion into the contused muscle. This environment also increased the number of proliferating and differentiating satellite cells and the amount of regenerated muscle fibers. In the early phase after injury, HBO stimulated the IL-6/STAT3 pathway in contused muscles. Our results demonstrate that HBO has a dual role in decreasing inflammation and accelerating myogenesis in muscle contusion injuries.

Highlights

Among soft tissue injuries, muscle contusion injury is the most common sport-related injury, for athletes and for recreational players
We demonstrated that Hyperbaric oxygen treatment (HBO) dramatically reduced hypoxia and that the oxygenized environment lasted for 30 hours after even only one session of HBO
During HBO, the oxygen concentration increased in the later half of 2.5 atmospheres absolute (ATA) (Fig. 1A), possibly as a result of decreased blood circulation caused by arterial constriction under the high oxygen concentration to maintain homeostasis[13]

Summary

Introduction

Muscle contusion injury is the most common sport-related injury, for athletes and for recreational players. Treatment options for muscle injury such as massage, cryotherapy, and hyperbaric oxygen treatment (HBO) are being considered for use in clinical practice. Among these treatments, HBO has been proposed to have the highest potential as an effective adjunct treatment for muscle recovery[3,4,5]. We developed a stable muscle contusion injury model in rats based on the mass-drop method, and evaluated how the hyperbaric and hyper-oxygenated environment affected oxygenation, inflammation and hindlimb swelling as acute changes, as well as myofiber regeneration as a subacute change, after injury

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