A Research On The Effects Of Resuscitation Ventilation In A Rat Model Of Traumatic Axonal Injury And Secondary Hypoxia

ObjectiveBased on the secondary brain injury(SBI) rat model of traumatic axonal injury followed by a post-traumatic hypoxic insult, we began to resuscitate using different oxygen concentrations, after that we explored the effects of different oxygen concentrations on the lipid peroxidation and histopathology in order to conclude the best stratergy of oxygen therapy for the rat model of traumatic axonal injury with hyoxemia.MethodsTAI and systemic hypoxia was induced by an impact-acceleration & rotation device and ventilating rats with 10% oxygen in nitrogen 30 minutes, respectively. After that the Adult Sprague-Dawley rats were given different concentrations of oxygen gas mixture 1 hour. Malondialdehyde ? superoxide dismutase and neurofilament protein immunohistochemistry results among those groups were systemically assessed and compared.ResultsCompared to the Sham, the level of malondialdehyde in TAI with hypoxia and each ventilating group increased obviously, however, 1w later the level returned to the normal. When ventilating with 21% and 50% oxygen the level of malondialdehyde fell significantly compared to TAI with hypoxia, The higher oxygen, the higher level of malondialdehyde. The level of superoxide dismutase in TAI with hypoxia and each ventilating group decresed significantly(P>0.05)compared to the Sham. Though the level increased after hypoxia,1w later was still under the normal. Differently ventilanting with 21% oxygen,the level of superoxide dismutase increased significantly(P<0.05),while the 50% and the 75% concentration insignificantly(P>0.05).In addition, while ventilating 100% oxygen, the level decreased significantly(P<0.05).With the development of the ventilationg oxygen, the level of superoxide dismutase decreased.NF200 immune staining in brainstem showed that when 24 h positive staining of TAI and hypoxia group was stronger than the resuscitation groups.When 21% oxygen concentration the positive staining was the weakest. The positive staining decreased over time. And 1w positive staining was weaker than that of 24 h.The positive staining of TAI combined with hypoxia group was obvious stronger than the recovery groups, and the positive staining in 21% oxygen concentration was the weakest. Positive staining of axonal semi quantitative analysis showed that it was significantly higher in 24 h TAI combined with hypoxia group than that of the resuscitation groups,with minimum value of 21% oxygen concentration. Numerical groups decreased with time,and 1 w value of each group was significantly lower than that in 24 h.Values in the TAI combined hypoxia group were still higher than the resuscitation groups,and the value of the 21% oxygen concentration still was the lowest.ConclusionsFrom the study we can conclude that oxygen therapy can correct and ameliorate hypoxemia in brain tissue, reduce the injury of lipid peroxidation, but the effects of different oxygen concentration are different respectively. Appropriately ventilating can significantly reduce axonal injury, playing a neuro protective role. For the best recovery to TAI combined with hypoxia in the animal model, the oxygen concentration should be less than 50%,otherwise the injury of brain tissue will be increased.