[Influences of gas explosion on acute blast lung injury and time phase changes of pulmonary function in rats under real roadway environment].

Objective: The aims of this study were to investigate the effect of gas explosion on rats and to explore the pulmonary function alterations associated with gas explosion-induced acute blast lung injury (ABLI) in real roadway environment. Methods: In April 2018, the large coal mine gas explosion test roadway and explosion test system were used to simulate the real gas explosion roadway environment, fixed the cage and set the explosion parameters. 72 SD rats, male, SPF grade, were randomly divided into nine groups by completely random grouping method according to their body weight: control group, close range group (160 m) , and long range group (240 m) . In each group, there were wound groups (24 h group and 48h group, 8/group, total 48 in six groups) and no wound groups (8/group, total 24 in three groups) . Except for the control group, the other groups were placed in cages at different distances under anesthesia, the experiment of gas explosion was carried out by placing the rats in a position that could force the lungs. The changes of respiratory function of the rats in the non-invasive group were monitored with pulmonary function instrument at 2 h, 24 h, 48 h, 72 h and 168h after the explosion, and were killed under anesthesia 7 days later; the rats in invasive groups were anesthetized and killed at 24 h, 48 h and 168 h, respectively. Gross observation, lung wet-dry ratio and lung histopathology were performed. Results: Compared with the control group, f (respiratory frequency, f) , MV (minute ventilation, MV) , PEF (peak expiratory flow rate, PEF) , PIF (peak inspiratory flow rate, PIF) and EF50 (1/2 tidal volume expiratory flow, EF50) of rats in the close and long range groups decreased significantly after gas explosion 2 h. PAU (respiration pause, PAU) , Te (expiratory time, Te) , Ti (inspiratory time, Ti) and Tr (relaxation time, Tr) were significantly increased (P<0.05) . After 48 h, TV (tidal volume, TV) , Penh (enhanced respiration pause, Penh) , PAU, and PIF of rats in the long range group were significantly increased (P<0.05) . After 72 h, MV in the long range group was significantly decreased (P<0.05) . Compared with the control group, Penh, PAU, Ti and Te were significantly decreased after 168 h in the close and long range groups, with statistical significance (P<0.05) . At the same time, the body weight of rats in different range groups was significantly decreased (P<0.05) . In addition, both HE staining and routine observation of lung tissues of rats in different range groups showed that gas explosion caused pulmonary edema, obviously congested pulmonary capillaries, a large number of inflammatory cells and infiltrated red blood cells. Conclusion: Gas explosion in real roadway environment can cause the change of respiratory function phase and lung tissue damage in rats, suggesting that the model of gas explosion-induced ABLI has been initially established successfully, which would provide a basis for further study on the pathogenesis of ABLI.

Protective effect of ulinastatin combined with dexmedetomidine on lung injury after cold ischemia-reperfusion in rats.

OBJECTIVE: We investigated the protective effect of ulinastatin combined with dexmedetomidine on lung injury after hepatic ischemia-reperfusion in rats. MATERIALS AND METHODS: A total of 60 healthy and clean male Sprague Dawley (SD) rats were divided into the blank control group (group O), the model control group (group K), the ulinastatin and dexmedetomidine group (group F) according to random number table with 20 rats in each group. RESULTS: The plasma concentrations of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), interleukin-8 (IL-8) and malondialdehyde (MDA) at T1, T2 and T3 time points in rats of the three groups were significantly higher than those of the T0 time point (p<0.05). The superoxide dismutase (SOD) activity in the plasma of rats of the three groups was significantly lower at T1, T2 and T3 time point when compared with that of T0 (p<0.05). The concentrations of TNF-α, IL-6, IL-8 and MDA in group K at T1, T2 and T3 moments were significantly higher than those of group O (p<0.05). However, the concentrations of IL-6, IL-8, TNF-α and MDA in group F at T1, T2, T3 were significantly lower than those of group K (p<0.05). The activities of SOD in group K at T1, T2, T3 were all significantly higher than those of group O (p<0.05). Meanwhile, the activities of SOD in group F at T1, T2, T3 were significantly higher than those of group K (p<0.05). CONCLUSIONS: Ulinastatin combined with dexmedetomidine can reduce the inflammatory response and inhibit lipid peroxidation, eventually alleviating acute lung injury after hepatic ischemia-reperfusion in rats.