| 摘要 |
Ischemia occurs frequently in various human pathologies and remains the leading cause of acute renal failure in adults. Physiological changes in the kidney suggest that ischemia-reperfusion injury alters the extracellular matrix. Matrix metalloproteinases (MMPs) are key proteolytic enzymes remodeling the matrix. Recently a strong stimulation of both latent and active forms of dimeric MMP-9 and the active monomeric MMP-9 was observed in glomeruli during kidney ischemia. Our objective was to investigate the ability of REGA-3G12 to inhibit selectively MMP-9 induced in glomeruli during renal ischemia in rats. Unilateral ischemia was induced by vascular clamping (30 min) followed or not by reperfusion (60 min) and isolation of glomeruli. REGA-3G12scFv in PBS solution was injected at a dosage of 5 mg/kg in the r at jugular vein at 1 h before ischemia. Results: Serum creatinine levels are an indicator of impaired glomerular filtration rate, an hallmark of acute renal failure. REGA-3G12 significantly prevented the increase of serum creatinine levels during the reperfusion. Gelatin zymography and Western blotting determined the activation and expression levels of gelatinases. REGA-3G12scFv blocks the upregulation of MMP-9 expression induced by ischem ia in glomeruli. MMP-9 upregulation during kidneyischemia led to degradation of tight junction zonula occludens-1 (ZO-1), an MMP-9 substrate. But, ZO-1 levels were higher in the presence of REGA-3G12 than in its absence demonstrating that both expression and in vivo activity of MMP-9 were inhibited by REGA-3G12. ProMMP-2 and MMP-2 levels were modulated by ischemia-reperfusion with similar patterns in the presence and absence of REGA-3G12 showing the specificity of REGA-3G12 action for MMP-9. In the presence of REGA-3G12, TIMP-1 was protected against proteolysis occurring during ischemia. In contrast, similar patterns of TIMP-2 were observed in the presence and in the absence of REGA-3G12 during ischemia-reperfusion. In conclusion, these data clearly demonstrate that REG A- 3G12 inhibits MMP-9 activity in a living animal generating new insights about the molecular mechanisms of REGA-3G12 to specifically block MMP-9 activity and expression. These data suggest a role for specific MMP-9 inhibitors in t he management of renal ischemic conditions.
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