| Objective In this study, we established a rat model of renal ischemic preconditioning to observe the changes of renal function, the content of MPO and SOD activity, renal histology, the gene expressions of intercellular adhesion molecule-1 (ICAM-1) and the DNA binding activity of nuclear factor-κB (NF-κB) in rat kidney in order to explore the effects of renal ischemic preconditioning improving acute ischemic injury in rat kidney and offer the experimental and theoretical evidence for the new choice in prevention and therapy acute renal failure. Methods The ischemia model with occlusion of left renal artery for 45min in a right-nephrectomized rat was used in this experiment. 30 male Wistar rats of part one were randomized into four groups. Group Sham(n=5): islation of left renal artery; Group IPC(n=5): 2 min of ischemia followed by 5 min of reperfusion, total of four cycles;Group I/R(n=10): warm ischaemia for 45 min; Group IPC-I/R(n=10): ischaemia for 45 min preceded by IPC pretreatment. All the animals were repurfused for 24 hours. 82 male Wistar rats of part two were randomized in eleven groups,the treatment of Group A1,B1,C1,D1 are the same as that of Group Sham,IPC,I/R,IPC-I/R in part one respectively with 10 rats in each group; the treatment of Group A2,B2,C2,D2 with 6 rats in each group are the same as that of Group A1,B1,C1,D1 respectively except for 2 hours repurfusion; the treatment of Group B3,C3,D3 with 6 rats in each group are the same as that of Group B2,C1,D1 respectively except for intraperitoneal injection of 150mg/kg PDTC 30 min before treatment.. The changes of serum creatinine level,the injury counts of renal tubule, myeloperoxidase (MPO) of renal medulla were evaluated at 24hour of reperfusion. The gene expressions of ICAM-1 of rats in part one were detected by reverse-transcription polymerase chain reaction (RT-PCR). At 2 hour of reperfusion, superoxide dismutase (SOD) was studied and the DNA binding activity of NF-κB in rat kidney was measured by electrophoretic mobility shift assay (EMSA ). Results (1) The change of serum creatinine level The increase range of serum creatinine in Group IPC-I/R is obviously lower than that in Group I/R (204.57±84.73μmol/L vs 291.68±56.21μmol/L, p<0.05),though the serum creatinine of the two groups obviously increased compared with Sham,IPC groups (p<0.01). There was no significant difference in serum creatinine between Group Sham and Group IPC. (2) Histological examination There are epithelial cells abscission,brush border abolition,tubule obstruction and interstitial edema in I/R group, but the tubule injury in IPC-I/R group was obviously attenuated and the injury counts of renal tubule decreased obviously(p<0.01) . (3) Renal medulla MPO activity There was marked decrease of MPO activity in IPC-I/R group compared with I/R group(0.96±0.46 vs 1.50±0.30 U/g wet tissue,p<0.05). (4) The gene expressions of ICAM-1 in renal tissue Compared with I/R group, marked decrease in gene expressions of ICAM-1 was observed in IPC-I/R group (p<0.01); and there was no significant difference in ICAM-1 gene expression between IPC-I/R group and Sham or IPC groups.(5) Significant positive correlation was observed between renal medulla MPO activity or injury counts of renal tubule and serum creatinine (p<0.01), between renal medulla MPO activity or serum creatinine and expression of ICAM-1 mRNA (p<0.01). (6) The change of serum creatinine level The increasing range of serum creatinine in Group D1 is obviously lower compared with Group C1(164.0±45.0μmol/L vs 232.1±87.1μmol/L, p<0.05), though the serum creatinine of the two groups obviously increased compared with A1,B1 groups. (p<0.01) . There was no significant difference in serum creatinine between Group A1 and Group B1.(7) The DNA binding activity of NF-κB in rat kidney Compared with A2 group, the DNA binding activity of NF-κB in B2 and C2 groups increased markedly and B3 group decreased markedly, the difference is significant (P<0.01), and the DNA binding activity of NF-κB in D2 group had no obvio... |
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