Aresearch Of Resuscitation Ventilation Strategy Ina Rat Modelof Traumaticaxonalinjuryand Secondary Hypoxia

ObjectiveBased on the secondary brain injury (SBI) rat model of traumatic axonalinjury followed by a post-traumatic hypoxic insult, we began to resuscitateusing different oxygen concentrations, after that we explored the effects ofdifferent oxygen concentrations on the blood gases and histopathology.MethodsTAI and systemic hypoxia was induced by an impact-acceleration&rotation device and ventilating rats with10%oxygen in nitrogen30min,respectively. Adult Sprague-Dawley rats were given different concentrationsof oxygen gas mixture1hour. Blood gas parameters, beta-amyloidprecursor protein immunohistochemistry results among those rats weresystemically assessed and compared.ResultsAfter ventilation resuscitation with different oxygen concentrations, namely between groups within60min and90min after injury, both PaO2and SaO2are basically the same. Giving21%oxygen gas mixture, PaO2rises rapidly, close to the normal level; when50%oxygen concentration,PaO2rises to1.8times of the normal; when75%oxygen concentration, is2times of the normal; when100%oxygen concentration, is2.9times of thenormal. Giving21%oxygen gas mixture, SaO2increases rapidly, close tothe normal level; when50%oxygen concentration, SaO2is close to100%; when75%,100%oxygen concentration, SaO2is100%.Beta-APP immune staining in brainstem ROI showes that when24h positive staining of TAI with hypoxia group is stronger than theresuscitation groups, when50%oxygen concentration the positive stainingis the weakest; the positive staining decreases over time,1w positivestaining is weaker than that in24h, the positive staining of TAI combinedwith hypoxia group was obvious stronger than the recovery groups, thepositive staining in50%oxygen concentration is the weakest. Positivestaining of axonal semi quantitative analysis showes that, when24h TAIcombined with hypoxia group is significantly higher than that ofthe resuscitation groups, minimum value of50%oxygen concentration;numerical groups decreased with time,1w value of each group issignificantly lower than that in24h, the TAI combined hypoxia group values still higher than the resuscitation groups,50%oxygen concentrationvalues still is the lowest.ConclusionsFrom the study we can conclude that oxygen therapy can improvearterial oxygen partial pressure and oxygen saturation after traumasignificantly, and with the oxygen concentration increases the arterialoxygen partial pressure gradually increases. Oxygen therapy cansignificantly reduce axonal injury, playing a neuroprotective role. For thebest recovery to TAI combined with hypoxia in the current animal model,the oxygen concentration is about50%.