Effect of different doses of dexmedetomidine on lung function and tissue cell apoptosis in a rat model of hyperoxic acute lung injury

Purpose: To study the effect of different doses of dexmedetomidine on lung function and lung tissue cell apoptosis in a rat model of hyperoxic acute lung injury. Methods: Five groups of healthy male Sprague-Dawley rats were used: normal rats, untreated hyperoxic rats, and hyperoxic rats given 3 different doses of dexmedetomidine, with 20 rats in each group. The levels of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were determined usingenzyme-linked immunosorbent assay (ELISA). Parietal paraffin cuts were taken from the right upper lobe for measurement of apoptosis using in situ terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), and the apoptosis index was calculated. Results: At 24 and 48 h, the levels of IL-6 and TNF-α in the hyperoxia model group were significantly higher than those in the normal control group, and their levels in the middle- and high-dose groups were markedly lowered, relative to untreated hyperoxia rats (p < 0.05). Apoptosis index in the hyperoxia model rats significantly increased, relative to normal rats (p < 0.05). The apoptosis index in the mediumand high-dose groups decreased significantly (p < 0.05). Conclusion: Dexmedetomidine inhibits inflammatory responses caused by high concentration of oxygen inhalation, minimizes lung injury, improves lung function and inhibits lung apoptosis. Keywords: Dexmedetomidine, Hyperoxia, Acute lung injury, Lung function, Apoptosis