Evaluation of an Injectable, Solid-State, Oxygen-Delivering Compound (Ox66) in a Rodent Model of Pulmonary Dysfunction-Induced Hypoxia

Abstract

Introduction: Pulmonary dysfunction (PD) and its associated hypoxia present a complication to the care of many service members and can arise intrinsically via comorbidities or extrinsically by infection or combat-related trauma (burn, smoke inhalation, and traumatic acute lung injury). Current supportive treatments (e.g., ventilation and supplemental oxygen) relieve hypoxia but carry a significant risk of further lung injury that drives mortality. Ox66 is a novel, solid-state oxygenating compound capable of delivering oxygen via intravenous infusion. Materials and Methods: Male Sprague Dawley rats (N =21; 250-300 g) were surgically prepared for cardiovascular monitoring, fluid infusion, mechanical ventilation, and intravital and phosphorescence quenching microscopy (interstitial oxygen tension; PISFO2) of the spinotrapezius muscle. Baselines (BL) were collected under anesthesia and spontaneous respiration. PD was simulated via hypoventilation (50% tidal volume reduction) and was maintained for 3 hours. Groups were randomized to receive Ox66, normal saline (NS; vehicle control), or Sham (no treatment) and were treated immediately following PD onset. Arterial blood samples (65 μL) and intravital images were taken hourly to assess blood gases and chemistry and changes in arteriolar diameter, respectively. Significance was taken at P < .05. Results: PD reduced PISFO2 for all groups; however, by 75 minutes, both NS and Sham were significantly lower than Ox66 and remained so until the end of PD. Serum lactate levels were lowest in the Ox66 group - even decreasing relative to BL - but only significant versus Sham. Furthermore, all Ox66 animals survived the full PD challenge, while one NS and two Sham animals died. No significant vasoconstrictive or vasodilative effect was noted within or between experimental groups. Conclusion: Treatment with intravenous Ox66 improved interstitial oxygenation in the spinotrapezius muscle - a recognized bellwether for systemic capillary function - suggesting an improvement in oxygen delivery. Ox66 offers a novel approach to supplemental oxygenation that bypasses lung injury and dysfunction.