Optical microsensing reveals spatiotemporal oxygen dynamics in cornea wounds that affect healing via reactive oxygen species

Abstract

Oxygen (O₂) metabolism plays a critical role in cornea wound healing, regeneration, and homeostasis; however, the underlying spatiotemporal mechanisms are poorly understood. Here we used an optical sensor to profile O₂ flux in intact and wounded corneas of mouse eyes. Intact corneas have unique centrifugal O₂ influx profiles, smallest flux at the cornea center, and highest at the limbus. Following cornea injury, the O₂ influx profile presents three distinct consecutive phases: a “decreasing” phase from 0 to 6 h, a “recovering” phase from 12 to 48 h, and a ‘peak’ phase from 48 to 72 h, congruent to previously described healing phases. Immediately after wounding, the O₂ influx drops at wound center and wound edge but does not change significantly at the wound side or limbus. Inhibition of reactive oxygen species (ROS) in the decreasing phase significantly reduces O₂ influx, decreases epithelial migration and consequently delays healing. The dynamics of O₂ influx show a positive correlation with cell proliferation at the wound side, with significantly increased proliferation at the peak phase of O₂ influx. This study elucidates the spatiotemporal O₂ dynamics in both intact and wounded rodent cornea and shows the crucial role of O₂ dynamics in regulating cell migration and proliferation through ROS metabolism, ultimately contributing to wound healing. These results demonstrate the usefulness of the micro-optrode in the characterization of spatiotemporal O₂ dynamics. Injury-induced changes in O₂ metabolism and ROS production modulate O₂ dynamics at wound and control cell migration and proliferation, both essential for proper wound healing.