Experimental Studies On The Protective Effects Of Hyperoxia Solution On Acute Rabbit Lung Injury Induced By Phosgene Poisoning And Part Of The Mechanisms

Phosgene belongs to blackdamp, as a chemical material, which is widely used in chemical industry and chemical weapons production. Phosgene may cause toxic pneumonia.diffusive and transudatory pulmonary edema, ARDS and death even. Usually,symptomatic treatment is utilized in clinical practice, among which redress of anoxia and lung edema are most valued. Although many things have been done about treatment of phosgene poisoning and progress have been made, there is no effective therapy by far. Because of dysfunction of air exchange in lung induced by phosgene poisoning, hypoxemia is hard to be redressed by oxeygen supply via respiratory tract. Recently, Hyperoxia solution (HO) is used in clinic as an effective way to treat anoxia diseases. This study investigated the effects of HO on phosgene-induced acute lung injury.Part 1 Experimental studies on Protective effects and investigate mechanism of hyperoxia solution infusion on acute rabbit lung injury induced by phosgene poisoningAIM: To investigate the protective effect and mechanism of hyperoxia solution infusion on rabbit with acute lung injury induced by phosgene. METHODS ONE: All rabbits were placed in the phosgene-exposure chamberand inhaled phosgene or fresh air for the same time period. 54 rabbits(weight 2.0 ~ 2.5kg) were randomly divided into nine groups(n=6): Control group(C group.with fresh air); High concentration phosgene group with four subgroups. Group HP: This group was only exposed to phosgene; Group HPB:After exposed to phosgene, this group received an infusion of balanced salt solution(BS.30mL kg-1) which was begun lh after phosgene exposure; Group HPH: HO was administered (30mL kg-1) to the rabbits(lh after exposure); Group HPP: HO was infused intravenously(30mL kg-1) 2h before phosgene exposure. Low concentration phosgene group with four subgroups too. Group LP was exposed to phosgene without any treatment; Group LPB was treated with BS(30mL kg-1); Group LPH was administered with HO (30mL kg-1); Group LPP received HO(30mL kg-1) 2h before phosgene exposure. Survival time of each rabbit was recorded in high concentration phosgene groups . Blood samples were taken at different time points for the determination of PaO2, plasma malordialdehyde (MDA) contents and superoxide dismutase(SOD) activity. The chests were opened and lungs removed. The wet left lungs were weight for L B-1, then after lavaging bronchoalveolar with 0.9% salt solution for plasma MDA contents and GSH - Px activity in bronchoalveolar lavage fluid ( BALF) , they were placed in an oven at 70 deg C and dried to a constant weight to measure W D-1, LW. Small piece of left lung was homogenized and analyzed tissue Glutathione (GSH/GSSG) contents. The remaining parts of left lung were collected to observe pathologic changes. METHODS TWO: Forty-two rabbits(weight 2.0 ~ 2.5kg) were randomly divided into seven groups: Group C inhaled air in the same chamber; BS group with three subgroups:Group B1 received low -dose BS(10ml kg-1) 1h after phosgene exposure ; Group B3 was administered medium-dose BS(30ml kg-1) and High-dose BS(50ml kg-1) was infused intravenously in Group B5 at the same time point; HO group with three subgroups too: Group H1 were treated with low-dose HO (10ml kg-1); Group H3 received medium-dose HO(30ml kg-1) and Group H5 were given by high -dose HO(50ml kg-1); Blood samples were taken from the animals at different time points after phosgene or air exposure for measurement of PaO2, plasma MDA contents and superoxide dismutase(SOD) activity; Glutathione (GSH/GSSG)contents in lung tissue and W D-1, LW and L B-1 were measured after the rabbits were executed. RESULTS ONE: (1) In high concentration phosgene groups, the survival time in HPH and HPP significantly prolonged in comparison with (P<0.05) HP and HPB. (2) In low concentration phosgene groups, the rate of W D-1, LW and L B-1 was significantly higher and PaO2 decreased in phosgene-exposed than in air-exposed control group. Exposure to phosgene greatly increased the formation of lipid peroxidation by-products in rabbit...