acetyl-aspartyl-glutamyl-valyl-aspartal and Reperfusion-Injury

Caspase activation has been implicated in the development of ischemia-reperfusion injury. Here, we investigate the effects of different caspase inhibitors on the renal dysfunction and injury caused by ischemia-reperfusion of the rat kidney. Bilateral clamping of renal pedicles (45 min) followed by reperfusion (6 h) caused significant renal dysfunction and marked renal injury. Caspase-1 inhibitor II (N-acetyl-L-tyrosyl-L-valyl-N-[(1S)-1-(carboxymethyl)-3-chloro-2-oxo-propyl]-L-alaninamide, Ac-YVAD-CMK, 3 mg/kg, administered i.p.) significantly reduced biochemical and histological evidence of renal dysfunction and injury. However, although caspase-3 inhibitor I (N-acetyl-L-aspartyl-L-glutamyl-N-(2-carboxyl-1-formylethyl]-L-valinamide, Ac-DEVD-CHO, 3 mg/kg, administered i.p.) produced a significant improvement of renal (glomerular) dysfunction (reduction of serum creatinine levels), it was not able to reduce tubular dysfunction and injury. Furthermore, the pan-caspase inhibitor caspase inhibitor III (N-tert-butoxycarbonyl-aspartyl(OMe)-fluoromethylketone, Boc-D-FMK, 3 mg/kg, administered i.p.) did not reduce renal dysfunction and injury. Both caspase-1 and -3 inhibitors markedly reduced the evidence of oxidative and nitrosative stress in rat kidneys subjected to ischemia-reperfusion. Overall, these results demonstrate that inhibition of caspase-1 reduces renal ischemia-reperfusion injury to a greater extent than caspase-3 inhibition, supporting the notion that the mode of acute cell death in our model of renal ischemia-reperfusion is primarily via necrosis. Furthermore, our finding that a pan-caspase inhibitor did not reduce the renal dysfunction and injury suggests that activation of some caspases during ischemia-reperfusion could provide protection against acute ischemic renal injury. Overall, these results demonstrate that inhibition of caspase-1 activity reduces renal ischemia-reperfusion injury and that this therapeutic strategy may be of benefit against ischemic acute renal failure.

Topics: Animals; Benzyl Compounds; Biomarkers; Caspase 3; Caspase Inhibitors; Cysteine Proteinase Inhibitors; Hydrocarbons, Fluorinated; Immunohistochemistry; In Vitro Techniques; Intercellular Adhesion Molecule-1; Kidney; Kidney Function Tests; Male; Malondialdehyde; Myocardium; Nitric Oxide; Oligopeptides; Organ Size; Oxidative Stress; Peroxidase; Rats; Rats, Wistar; Reperfusion Injury; Serpins; Tyrosine; Viral Proteins

To evaluate possible roles of caspase-1 and caspase-3 in retinal ischemia-reperfusion injury.. Retinal ischemia was induced in rats by increasing the intraocular pressure to 110 mm Hg for 60 minutes. Expression of caspase-1 and caspase-3 was studied at the mRNA and protein levels using immunohistochemical staining, western blot analysis, semiquantitative reverse transcription-polymerase chain reaction, and assay of the enzymatic activities. Apoptotic retinal neurons were detected by the TdT-dUTP terminal nick-end labeling (TUNEL) method. To study the roles of the caspases in retinal ischemia-reperfusion injury, an inhibitor of caspase-1, acetyl-tyrosyl-valyl-alanyl-aspart-1-al (Ac-YVAD-CHO; total dose, 10(-7) moles) and that of caspase-3, acetyl-aspartyl-glutamylvalyl-aspart-1-al (Ac-DEVD-CHO; total dose, 10(-7) moles) was injected intravitreally and the number of TUNEL-positive cells was compared with the number in sections not treated with the inhibitors.. In the inner nuclear layer (INL), caspase-3-like immunoreactivity was predominantly detected, whereas caspase-1-like immunoreactivity was more predominant in the outer nuclear layer (ONL). Expression of caspase-1 and -3 was upregulated at the protein and gene levels 24 hours after reperfusion. Intravitreal injection of Ac-DEVD-CHO decreased the number of TUNEL-positive cells more significantly in the INL than in the ONL (P < 0.01) at 24 hours, whereas, intravitreal injection of Ac-YVAD-CHO was more effective in decreasing the number in the ONL (P < 0.05).. These findings suggest a possibility that cell-type-specific activation of caspases takes place in retinal ischemia-reperfusion injury, and such caspase may induce retinal neuronal cell death.

Topics: Animals; Apoptosis; Blotting, Western; Caspase 1; Caspase 3; Caspase Inhibitors; Caspases; Cysteine Proteinase Inhibitors; DNA Primers; Fluorescent Antibody Technique, Indirect; Gene Expression; In Situ Nick-End Labeling; Male; Neurons, Afferent; Oligopeptides; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Retina; Reverse Transcriptase Polymerase Chain Reaction; Up-Regulation