Experimental Study Of Protective Effect Of The Combination Of Verapamil And Glutathione On Allograft Rabbit Lung

Lung transplantation as an effective treatment for terminal stage lung diseases was really achieved success in clinical in 1983. In the past 20 years, there were some progresses in the study of the condition of lung preservation, but still lacking foundational research results. In order to look for better lung protective measure, and make the injury lessen, further study should concentrate on the mechanism of hypothermia metabolism and lung ischemical reperfusion injury which is not still clear.Currently the method for lung preservation in clinical which is widely used is the combination of the lung artery perfused purely and hypothermy .The best temperature for the lung perfused and preserved is still not very clear. Although it have confirmed that there is better effect at 10℃than at 4℃, majority experiment still adopt 4℃for lung perfused and preserved. There is Euro-collins solution (EC), UW solution and low potassium dextran solution (LPD) for lung preservation. Because high potassium perfusion can cause vessel contractive, cause perfusion pressure goes up and perfusion asymmetrical, and ischemical reperfusion injury is aggravated, So currently the LPD solution is widely used, it is better distribute in the lung vessel, the glucose it contains can increase energy storage, lung function is improved.Along with the understanding of the mechanism of ischemical reperfusion injury intro- and post-preservation, currently various medicine was applied to be assistant condition for lung preservation in the experiment or clinical, resisted with the bad results. With the prolong of the preservation time, Ca²⁺ out of the cell comes into the cell for the density steps, particularly after reperfusion, the calcium overload happens, and it inducts a series of cell toxicity reaction. In the meantime, the oxygen free radicals are in a great deal of formation inside the body, the free radicals can make adipose membrane over oxidation, and hurt cell DNA, also oxidize pulmonary surfactant and cause the lung function damaged. Current experiments confirmed that Ca²⁺ antagonism and the oxygen free radicals scavenger could lessen lung ischemical reperfusion injury. Whether combination application has a better function and the relationship of the two kinds of mechanism of the medicine function currently still have no hard conclusion.In this experiment orthotropic pulmonary allograft transplant model in rabbit was established and the donor lung was flushed and preserved by the modified LPD Lung preservative solution in which Verapamil and Glutathione was added, and the pulmonary protective effect of verapamil and glutathione on allograft rabbit lung was investigated.Part 1 The experiment of the establishment of rabbit orthotropic pulmonary allotransplantation modelObjective To establish orthotropic pulmonary allotransplantation model in rabbit, which has high achievement ratio and low-grade operation difficulty.Methods Fifty-two rabbits were randomly divided into donor and recipient groups .The donor lung was preserved 4 hours in the lung protective solution in 4°C, and Anatomists of bronchi, pulmonary artery and pulmonary vein was performed by the stent technique. the stent for pulmonary artery and vein was maked by the Plastic tube which diameter was 1.5～2.0mm, and the stent for bronchi was maked by the Plastic tube which diameter was 4～5mm.The reperfusionwould last 2 hours.Results In 26 cases of operations. anastomosis was finished successfully. The time of donor lung picked and anatomized was (40±5)min. the time of recipient anatomized was (38±4)min.Because of obstructed artery, two cases were found there was no blooding from the pulmonary vein. Dysfunction of vein and bronchi was not found. The structure of lung was integrity as proved by pathological section, achievement ratio was 92.3%.Conclusion The model is definite as the achievement ratio raised and the degree of operation difficulty was degraded, and it is easy for learner to use.Part 2 Experimental study of protective effect of the combination of Verapamil and Glutathione on allograft rabbit lungObjective 1. To confirm the protective effect of Verapamil and Glutathione on allograft rabbit lung;2. To investigate the protective effect of the combination of verapamil and glutathione on allograft rabbit lung;3. To investigate the influence of Verapamil to the the free radicals;4. To investigate the influence of Glutathione to the Ca²⁺ in the cell. Methods 24 pairs rabbits were randomly divided into 4 groups: D group(n= 6 pairs, control), lungs were flushed and preserved by modified LPD solution; Y group(n=6 pairs): lungs were flushed and preserved by modified LPD solution plus verapamil 2mg/kg; H group(n=6 pairs): lungs were flushed and preserved by modified LPD solution plus glutathione 3mmol/L; L group(n=6 pairs): ungs were flushed and preserved by modified LPD solution plus verapamil 2mg/kg and glutathione 3mmol/L.All lungs were preserved for 4 hours in 4℃, and lung tissue MDA and SOD, wet-to-dry weight ratio, intracellular Ca²⁺, lung permeability and apoptosis were measured after 2 hours reperfusion.Results Lung tissue MDA and SOD, wet-to-dry weight ratio, intracellular Ca²⁺, lung permeability in L group were better than other groups(P<0.05), in Y group and in H group were also better than in D group. Apoptosis in L group was obviously better than in D group.Conclusions 1. Verapamil and glutathione have protective effect for donor lung;2. Drug combination has better protection to the lung transplantation than alone;3. Verapamil can get rid of part of the free radicals;4. Glutathione also can eliminate the Ca²⁺ in the cell.