The Research Of L-Arginine Protective Effects On Donor Lung In Combined Heart-lung Transplantation

Objective: The study was to investigate the protective of L-Arginine on donor lung and possible mechanism in combined heart-lung transplantation.Methods: 20 adult healthy dogs were randomly divided into two groups without consideration of gender,each group has 10 dogs. One experiment needs a donor canine and a receptor canine.In the control group, the donor lungs were flushed with and preserved in (Low-Potassium dextran LPD)solution at 4℃.In the experimental group, the donor lungs were flushed with and preserved in cold(Low-Potassium dextran LPD)solution added with L-Arginine (500mg/kg)at 4℃.Arterial blood for the assay were drawn (PaO₂ ,PaCO₂).The protective effects was assessed by measuring the contents of nitric oxide(NO),superoxide dismutase(SOD) and malon -dialdehyde(MDA) in the donor lung tissues, and the ultrastructural studies of donor lung. After finishing the observation, the tissue specimens were taken for analysis of wet/dry ratio(W/Dr). All values were compared to the control group.Results: In experimental group ,arterial blood PaO₂ was significantly higher than that in control group at any appointed time points(P<0.05, P<0.01).However, arterial blood PaCO₂ was significantly lower than in control group at any appointed time points(P<0.05, P<0.01). The concentration of NO and SOD in the lung tissue was statistically higher in experimental group than that in control group(P<0.01).However, the MDA concentration was lower in experimental group than that in control group(P<0.05). JEM—100CX transmission electron microscopic examination showed the lesions in experimental group was milder than that in control group. The W/Dr determination revealed that the donor lungs in experimental group was less injuries than that in control group.Conclusion: Administration of exogenous L-Arginine (500mg/kg) in (Low Pot- assium dextran LPD)solution at 4℃in combined heart-lung transplantation can improve graft lung function, significantly attenuate the canine donor lung injury and increase the successful rate of CHLT. The protective mechanism maybe due to increase NO production and inhibit the production of oxygen free radicals and lipid peroxide following ischemic reperfusion, increase endogenous anti-oxidative ability, and improve canine donor lung clearout ability of endogenous oxygen free radicals .