RESUMO
【Objective】 To investigate the effects of high-dose hyperbaric trioxygen autologous blood therapy (HOT) on oxygenation index (PaO2/FiO2) and serum inflammatory factors in dogs with acute respiratory distress syndrome (ARDS). 【Methods】 Twelve healthy adult beagles were randomly divided into 3 groups (n=4). The blank group was injected with normal saline intravenously. The ARDS model was established by intravenous injection of oleic acid (0.12 mL/kg) in the ARDS group and ARDS+ HOT group. The mark of a successful model is that the oxygen and index (PaO2/FiO2) <300 mmHg. In the ARDS+ HOT group, after the ARDS model was established, 16 G indwelling needle was used to puncture the left femoral vein and connect the line of the HOT device. Venous blood (50 mL/ dog) was collected from the femoral vein under negative pressure to the blood storage bottle (100 mL blood storage bottle), and then the blood collection was stopped and the gas injection switch of the HOT device was turned on. Inject 50 mL of 20ng/dL trioxygen gas into the blood storage bottle. After gas injection, turn the blood storage bottle upside down three times to fully trioxidize the blood and then inject it back into the dog. Repeat this treatment for 10 cycles. PaO2 and PaO2/FiO2 were detected before treatment and at 1, 2, 3, 4, 5 h after treatment. The serum was retained after treatment, and the expressions of inflammatory cytokines (IL-6, IL-8) and myeloperoxidase (MPO) were detected by ELISA. The animals were euthanized, and the gross lung morphology of the dogs was observed at autopsy. The dorsal segment of the left lower lobe of the lung was taken for pathological section HE staining, and the morphological changes of the lung tissue were observed under the microscope. 【Results】 After 5 hours of treatment, the PaO2/FiO2 of blank group was 481.85±35.31, and that of ARDS group was 183.67±20.18, which was significantly lower than that of blank group (P<0.01). The ARDS HOT group was 271.90±21.35, which was significantly higher than the ARDS group (P<0.01). The inflammatory factor IL-6 was (206.49±38.85) pg/mL in the blank group, and (293.12±30.38) pg/mL in the ARDS group, which was significantly higher than that in the blank group (P<0.01). There was a significant difference between the ARDS HOT group and ARDS group (221.56±46.69) pg/mL (P<0.01). The results of inflammatory factor IL-8 detection showed that the IL-8 in ARDS group was increased compared with the blank group (P<0.01); and the IL-8 in ARDS HOT group was decreased compared with ARDS group (P<0.01). Myeloperoxidase MPO test results showed that the blank group was (505.58±73.94) pg/mL, and the ARDS group was (605.69±108.88) pg/mL, which was significantly higher than the blank group (P<0.05). The ARDS HOT group was (476.52±103.85) pg/mL, which was significantly lower than the ARDS group (P<0.05). Microscopic examination of lung pathology showed that the lung tissue injury in ARDS HOT group was significantly reduced compared with ARDS group. 【Conclusion】 HOT can reduce the inflammation and injury of lung in ARDS model dogs through significantly increasing the PaO2/FiO2, down-regulating the expression of MPO, then inhibiting the activity of neutrophils and reducing the levels of IL-6 and IL-8.