Effects of nifedipine and platelet activating factor antagonist (BN 52021) in glycerol-induced acute renal failure in rats

Fasudil ameliorates rhabdomyolysis-induced acute kidney injury via inhibition of apoptosis

During times of war or natural disasters, rhabdomyolysis leading to acute kidney injury (AKI) can assume epidemic proportions. Fasudil attenuates ischemia/reperfusion-induced AKI. We investigated the therapeutic effect of an early application of fasudil on AKI induced by rhabdomyolysis and explored the potential mechanisms. Male Wistar rats were randomly divided into a control group (saline, 7 mL/kg, i.m.), a Gly group (50% glycerol, 7 mL/kg, i.m.), and a fasudil group (50% glycerol, 7 mL/kg, i.m.; fasudil, 20 mg/kg bodyweight, i.p., three times every 24 h beginning 72 h before glycerol administration). Serum creatinine, blood urea nitrogen (BUN), and histopathological changes were used to demonstrate kidney function 24 h after the glycerol injection. Cell apoptosis and the expression of rho-associated protein kinase member (ROCK1), phosphatase and tensin homolog (PTEN), P-Akt, and caspase-8, -9, and -3 were measured. Serum creatinine and BUN levels increased significantly in Gly group compared with control group. Both levels decreased after fasudil treatment. The renal tubular damage score was significantly lower and cell apoptosis was significantly less in fasudil group compared with Gly group. The expression levels of ROCK1, PTEN, and caspase-8, -9, and -3 were upregulated significantly in Gly group, and their expression was reduced in the fasudil group. The P-Akt level was decreased in Gly group and upregulated significantly in fasudil group. Early application of fasudil reduced rhabdomyolysis-associated renal injury by inhibiting Rho kinase and thereby activating the PI-3K/Akt pathway, which decreased cell apoptosis via both the intrinsic and extrinsic apoptotic pathways.

Effect of Nitric Oxide Synthase Inhibition and Saline Administration on Blood Pressure and Renal Sodium Handling During Experimental Sepsis in Rats

Much effort has been made in recent years to clarify metabolic and renal function changes in sepsis. A number of studies performed in different models of sepsis have been described. One such model that is frequently used is cecal ligation and puncture (CLP) in rats. This model resembles human sepsis in several important aspects, such as an early phase of hyperdynamic, hypermetabolic sepsis followed by a late hypodynamic, hypometabolic phase. The present study evaluated the blood pressure (n = 5) and renal function changes during development of CLP renal failure and to determine the effects of NOS inhibition (L-NAME) and 0.15 M NaCl administration on tail blood pressure and renal function in randomly assigned five groups (n = 10 each): (1) Sham-operated, (2) Sham-operated L-NAME-treated, (3) CLP rats, (4) CLP L-NAME-treated, and (5) CLP 0.15 M NaCl-treated rats. The basal tail blood pressure was not significantly different among the four groups. One week later, arterial pressure was significantly increased in sham-operated L-NAME-treated rats (159 +/- 12 mmHg) compare with the other groups (118 +/- 9.0 mmHg in nontreated rats, p < 0.05). Blood pressure shows a slightly and not significant decrease up to 12h in L-NAME and 0.15 M NaCl treated rats, which in turn was followed by a significant reduced arterial pressure 18h after CLP in both groups (L-NAME: 96.0 +/- 3.6 mmHg, p < 0.05) and NaCl: 82.3 +/- 2.4 mmHg, p < 0.05) compared to sham-operated groups. The glomerular filtration rate estimated by CCr decreases significantly in the CLP untreated group (p < 0.001) and did not significantly differ from the sham-operated and L-NAME-treated groups (p = 0.4) during the studies of renal tubule sodium handling. On the other hand, subcutaneous 0.15 M NaCl administration prevented CCr decreases in CLP rats (p = 0.25). CLP increased the FENa in the sham-operated from: 857.2 +/- 85.1 delta%min(-1) to CLP: 1197.8 +/- 119.0 delta%min(-1). The high FENa to CLP was blunted and significantly reduced by previous systemic treatment of animals with L-NAME from sham-operated+L-NAME: 1368.0 +/- 72.0 delta%min(-1) to CLP+L-NAME: 1148.0 +/- 60.4 delta%min(-1) (p < 0.01). The enhanced FENa in the CLP group were accompanied by a significant increase in proximal sodium reabsorption rejection. The salient findings of the present study suggest that a decrease in the blood pressure and creatinine clearance caused by CLP may benefit from L-NAM and fluid resuscitation during initial bacteremia (first 12 h) by promoting an additional increase of tubule sodium reabsorption in the post-proximal segments of nephrons, but these therapies could not prevent acute renal failure after established endotoxemia.

Reversal of Experimental Myoglobinuric Acute Renal Failure in Rats by Quercetin, a Bioflavonoid

The occurrence of acute renal failure (ARF) following rhabdomyolysis has been put at between 10 and 40% of cases, and accounts for between 3 and 15% of all cases of ARF. Reactive oxygen intermediates have been demonstrated to play an etiological role in myoglobinuric renal failure. This study was performed to explore the protective effect of quercetin, a bioflavonoid, in an experimental model of myoglobinuric ARF in rats. Four groups of rats were employed in this study: group 1 served as control, group 2 was given 50% glycerol (8 ml/kg, i.m.), group 3 was given glycerol + quercetin (2 mg/kg, i.p.), and group 4 was given glycerol + DMSO (the solvent for quercetin, 5 ml/kg, i.p.). Renal injury was assessed by measuring serum creatinine, blood urea nitrogen, creatinine and urea clearance. The oxidative stress was measured by renal malondialdehyde levels, reduced glutathione levels and by enzymatic activity of catalase, glutathione reductase, and superoxide dismutase. Glycerol administration resulted in a marked renal oxidative stress, significantly deranged the renal functions as well as renal cytoarchitecture. All these factors were significantly improved by quercetin treatment. Because of its radical-scavenging and iron-chelating properties, quercetin protected the kidney against the glycerol-induced oxidative stress and resultant renal dysfunction. Based on these results, this study confirms the role of oxidative stress and demonstrates the renoprotective potential of quercetin in this rhabdomyolysis-mimicking model.

Potential role of platelet activating factor in acute renal failure

The clinical condition of acute renal failure (ARF) can be caused by a diverse number of renal injuries, but it is generally characterized by a sharp reduction in the glomerular filtration rate (GFR). A lipid mediator, platelet activating factor (PAF), may be one of the entities responsible for causing the hemodynamic changes in the ARF kidney because it can act as a vasodilator or vasoconstrictor, depending upon its concentration. This review examines the action and mechanisms of PAF in experimental animal models of ischemia and nephrotoxicity, as well as renal failure associated with extrarenal disease. While further research is necessary before extrapolating our current knowledge of PAF into the prevention of renal failure of therapeutic intervention using PAF antagonists in human ARF, there is reasonable evidence to support its role as a mediator of the decrease in GFR characteristic of ARF.

Prophylaxis of acute renal failure in patients with rhabdomyolysis

Patients that develop rhabdomyolysis of different causes are at high risk of acute renal failure. Efforts to minimize this risk include volume repletion, treatment with mannitol, and urinary alkalinization as soon as possible after muscle injury. This is a retrospective analysis (from January 1, 1992, to December 31, 1995) of therapeutic response to prophylactic treatment in patients with rhabdomyolysis admitted to an intensive care unit (ICU). The diagnosis of rhabdomyolysis was based on creatinine kinase (CK) level (> 500 Ui/L) and the criteria for prophylaxis were: time elapsed between muscle injury to ICU admission < 48 h and serum creatinine < 3 mg/dL. Fifteen patients were treated with the association of saline, mannitol, and sodium bicarbonate (S + M + B group) and 9 patients received only saline (S group). Serum creatinine at admission was similar in both groups: 1.6 +/- 0.6 mg/dL in the S + M + B group and 1.5 +/- 0.6 mg/dL in the S group (p > 0.05). Maximum serum CK measured was 3351 +/- 1693 IU/L in the S + M + B group and 1747 +/- 2345 IU/L in the S group (p < 0.05). However the measurement of CK was earlier in S + M + B patients (1.7 vs 2.7 days after rhabdomyolysis). APACHE II scores were 16.9 +/- 7.4 and 13.4 +/- 4.9 in the S + M + MB and S groups, respectively (p > 0.05). Despite the treatment protocol the serum levels of creatinine had similar behavior and reached normal levels in all patients in 2 or 3 days. The saline infusion during the first 60 h on the ICU was 206 mL/h in the S group and 204 mL/h in S + M + B (p > 0.05). Mannitol dose was 56 g/day, and bicarbonate 225 mEq/day during 4.7 days. Our data show that progression to established renal failure can be totally avoided with prophylactic treatment, and that once appropriate saline expansion is provided, the association of mannitol and bicarbonate seems to be unnecessary.