Short ischemia induces rat kidney mitochondria dysfunction

Abstract

Renal artery clamping itself induces renal ischemia which subsequently causes renal cell injury and can lead to renal failure. The duration of warm ischemia that would be safe for postoperative kidney function during partial nephrectomy remains under investigations. Mitochondria play an important role in pathophysiology of ischemia-reperfusion induced kidney injury, however relation between ischemia time and mitochondrial dysfunction are not fully elucidated. Thus, the effects of renal ischemia (20 min, 40 min and 60 min) on mitochondrial functions were investigated by using in vitro rat ischemia model. Thus, electronmicroscopy showed that at short (20 min) ischemia mitochondria start to swell and the damage increases with the duration of ischemia. In accordance with this, a significant decrease in mitochondrial oxidative phosphorylation capacity was observed already after 20 min of ischemia with both, complex I dependent substrate glutamate/malate (52%) and complex II dependent substrate succinate (44%) which further decreased with the prolonged time of ischemia. The diminished state 3 respiration rate was associated with the decrease in mitochondrial Complex I activity and the release of cytochrome c. Mitochondrial Ca(2+) uptake was diminished by 37-49% after 20-60 min of ischemia and caspase-3 activation increased by 1.15-2.32-fold as compared to control. LDH activity changed closely with increasing time of renal ischemia. In conclusion, even short time (20 min) of warm ischemia in vitro leads to renal mitochondrial injury which increases progressively with the duration of ischemia.

Caffeic Acid Phenethyl Ester Reduces Ischemia‐Induced Kidney Mitochondrial Injury in Rats

“…The model of 20 and 40 min kidney ischemia in vitro was chosen because, according to our results [ 15 ], 20 min was the shortest period of ischemia that induced statistically significant changes in renal mitochondrial respiratory functions. Moreover, our results showed that 40 min of kidney ischemia induced much more severe mitochondria structural and metabolic changes.…”

“…Ultrastructural investigation revealed that CAPE had protected from ischemia (20 min)-induced mitochondrial damage. Previously, we have demonstrated that ischemia mainly affects the mitochondrial intermembrane space, where intracristal space was found enlarged resulting in ballooned cristae as well as enlarged peripheral space followed by detachment of outer and inner membranes [ 15 ]. Application of CAPE preserved intermembrane space from edema after 20 min of ischemia, as it was found narrow and uniform in all experimental groups.…”

“…Mitochondrial calcium uptake capacity was measured fluorimetrically (at 37°C) with Calcium Green-5N (excitation at 506 nm, emission at 535 nm) in medium containing 200 mM sucrose, 1 mM KH 2 PO 4 , 10 mM Tris-HCl, 10 μ M EGTA, 0.3 mM pyruvate plus 0.3 mM malate, pH 7.4, and 0.05 mg/ml of mitochondrial protein as described previously [ 15 ]. For calibration of the signal, known amounts of CaCl 2 (100 μ M) were added.…”

“…The control and ischemic samples of 1-2 × 2-3 mm from the kidneys were transferred to the fixative buffer containing 2.5% glutaraldehyde in 0.1 M phosphate buffer (pH 7.4). The taken samples were stored in fixative for at least 4 h at room temperature or overnight at 4°C and analyzed as described in [ 15 ].…”

The Role of PGC-1α and Mitochondrial Biogenesis in Kidney Diseases

“…Ischemia-reperfusion injury. Kidney IRI is a frequent cause of AKI after major surgery and following kidney transplantation that is characterized by PGC-1α downregulation and mitochondrial dysfunction [31,[171][172][173][174][175][176]. Kidney PGC-1α is reduced within 24 hours of kidney IRI, and PGC-1α-deficient mice had more severe AKI and accumulated fatty acids in tubular cells.…”