Effects of L-arginine and aminoguanidine on ischemia-reperfusion injury following rat lung transplantation

Abstract

Objective To investigate the effects of L-arginine (L-Arg) and aminoguanidine on ischemia-reperfusion injury following rat lung transplantation. Methods The models of rats lung transplantation were established and 4 groups ( n = 6 each) were randomly set up: group A ( normal control group)and treated groups B, C and D. In these groups, different medicines (NS, group A; L-Arg, group B;aminoguanidine, group C; L-Arg and aminoguanidine, group D) were intraperitoneally administered to the recipient rats before reperfusion. After reperfusion for 2 h, the lung graft was harvested for measurements of lung wet/dry ratio ( W/D ) , myeloperoxidase ( MPO ) , malondialdehyde ( MDA ) , superoxide dismutase (SOD) , endothelial nitric oxide synthase (eNOS) , inducible nitric oxide synthase (iNOS). The contents of plasma nitric oxide (NO) were determined. The pathological changes in the lung grafts were observed.Results After reperfusion for 2 h, W/D (5. 10 ±0.21), MPO (1.74 ±0.26) U/g, MDA (20.87 ±2. 90) μmol/g in group B were significantly lower [W/D (5. 74 ± 0. 14), MPO (2. 36 ± 0. 32) U/g,MDA (31. 33 ±3.46) μmol/g] (P ＜ 0. 05), and the levels of SOD (424. 29 ± 27. 86) U/mg protein,NO (175. 12 ± 17. 40) μmol/L, iNOS (3. 62 ±0. 26) U/mg protein and eNOS (5. 36 ±0. 28) U/mg protein were significantly higher than in group A [SOD (268.01 ±26.06) U/mg protein, NO (98.29 ±6.95) μmol/L, iNOS (2.53 ±0.22) U/mg protein and eNOS (3. 57 ±0.40) U/mg protein] (P＜0. 05). The contents of NO (84. 13 ±5. 18) μmol/L and iNOS (1. 81 ±0. 09) U/mg protein in group C were significantly lower than in group A (P ＜ 0. 05). W/D (4. 79 ± 0. 19) , MPO (1. 24 ± 0. 13 ) U/g,MDA (14. 60 ±4. 14) μmol/g, iNOS (1. 99 ±0. 17) U/mg protein were significantly lower than in group A (P ＜0. 05) , and SOD (493. 75 ±24. 95) , NO (149. 61 ± 10. 70) μmol/L and eNOS (5. 50 ±0. 27)U/mg protein in group D were significantly higher than in group A (P＜0. 05). W/D, MPO, MDA, NO and iNOS in group D were significantly reduced as compared with group B (P ＜ 0. 05 ) , and SOD was significantly increased in group B ( P ＜ 0. 05 ) . The pathological examination revealed that the inflammatory cell infiltration in group D was the mildest, followed by groups B, A and C. Conclusion The L-Arg could alleviate the lung ischemia-reperfusion injury after transplantation, the combined used of L-Arg and aminoguanidine could obtain better effects than L-Arg used alone. The aminoguanidine used alone could not alleviate ischemia-reperfusion injury after transplantation. Key words: Lung transplantation; Reperfusion injury; Nitric oxide synthase; Arginine; Aminoguanidine