In Vitro Modulation of Murine Tenocyte Behavior by Hyperbaric Oxygen Therapy

Tendon injuries often result in prolonged healing and excessive scar tissue formation due to chronic hypoxia in this poorly perfused tissue. Hyperbaric oxygen therapy (HBOT), a non-invasive treatment currently used for chronic wounds, may improve tendon healing by relieving hypoxia. However, the effects of HBOT on tendon cells, particularly tenocytes, remain poorly understood. This study investigated the in vitro effects of HBOT on murine Achilles tenocytes cultured under basal and inflammatory conditions induced by interleukin-1 beta (IL-1β). Tenocytes were exposed to 30, 60, or 90 min of HBOT at 2.5 atmospheres absolute (ATA) and assessed for changes in in vitro wound healing using a scratch assay, mitochondrial activity, cell viability, collagen deposition, and gene expression at 24- and 72-h post-treatment. HBOT increased collagen deposition, while transiently suppressing gene expression of collagen types I and III immediately following HBOT treatment, along with reduced expression of the oxygen responsive gene HIF-1α. Mitochondrial activity increased significantly at 24 h following longer HBOT exposure but remained unchanged with IL-1β. Cell viability remained high across all groups, although HBOT-treated wells visually showed slightly more dead cells. Inflammatory conditions revealed a significant reduction in wound closure in HBOT-treated tenocytes compared to controls. These findings suggest that HBOT can modulate mitochondrial activity, extracellular matrix (ECM) production, and gene expression in tenocytes, with differential effects in the presence of inflammation. Overall, this study provides new insights into the cellular effects of HBOT on tendon biology and supports further investigation into its therapeutic potential for tendon repair.