Prolonged compression of limb muscles and subsequent decompression are important in the development of crush syndrome (CS). We applied a simple rubber tourniquet to rat hind limbs to create a CS model. Anesthetized rats were subjected to bilateral hind limb compression for 5 hours followed by decompression and reperfusion for 0 hour, 1 hour, 3 hours, and 24 hours under monitoring of arterial blood pressure and electrocardiography. Blood and tissue samples were collected for histology, biochemical analysis, and tissue myeloperoxidase activity assessment. The survival rates of the CS-model groups remained at 100% until 3 hours, however, dropped to 25% at 24 hours after reperfusion mainly because of hyperkalemia and consequent hypotension observed at 1 hour and deteriorated at 3 hours after reperfusion. Rhabdomyolysis evaluated by circulating and histologic markers of injury was found as early as 1 hour and more marked at 3 hours, resulting in impaired renal function 24 hours after reperfusion. Myeloperoxidase activities increased with incremental periods after reperfusion not only in injured limb muscles but also in kidney and lung, suggesting an abnormal interaction between the vascular endothelium and circulating leukocytes after rhabdomyolysis, possibly causing subsequent multiple organ dysfunction frequently encountered in CS. The findings from this study demonstrate the feasibility of a novel small animal model of extremity crush injury. By using this model, the impact of incremental periods of reperfusion on mortality and remote organ dysfunctions can be characterized. Future studies are necessary to better define a threshold for this injury pattern and the impact of other factors underlying this syndrome.

Crush syndrome (CS) is a serious medical condition characterized by muscle cell damage resulting from decompression after compression (i.e., ischemia/reperfusion injury). A large number of CS patients develop cardiac failure, kidney dysfunction, and systemic inflammation, even when fluid therapy is administered. We evaluated whether the administration of astragaloside-IV (AS)-containing fluid improved survival by preventing kidney and muscular mitochondrial dysfunction in a rat model of CS. The CS model was generated by subjecting anesthetized rats to bilateral hind limb compression with a rubber tourniquet for 5 h. Rats were then randomly divided into four groups: (1) sham; (2) CS with no treatment; (3) CS with normal saline treatment; and (4) CS with normal saline + 10 mg/kg AS. AS-containing fluid improved kidney function by improving shock and metabolic acidosis in CS rats. In addition, there was a reduction in oxidative damage. The attenuation of hyperkalemia was significantly related to improving muscle injury via preventing mitochondrial dysfunction. Moreover, this mitochondria protection mechanism was related to the nitric oxide (NO) generated by activation of endothelial nitric oxide synthase, which provided an anti-oxidative and anti-inflammatory effect. Treatment with AS-containing fluid led to a dramatic improvement in survival following CS because of direct and indirect anti-oxidative effects in the kidney, and improvements in mitochondrial dysfunction and inflammation owing to AS acting as an NO donor in injured muscle.

The rheological properties of red blood cells (RBCs) play an important role in their microcirculation. RBCs can elastically deform in response to mechanical forces to pass through narrow vessels for effective gas exchange in peripheral tissues. Decreased RBC deformability is observed in lifestyle-related diseases such as diabetes mellitus, hypercholesterolemia, and hypertension, which are pathological conditions linked to increased oxidative stress and decreased nitric oxide (NO) bioavailability. Redox-sensitive cysteine residues on RBC cytoskeletal proteins, such as α- and β-spectrins, responsible for membrane flexibility, are affected by prolonged oxidative stress, leading to reversible and irreversible oxidative modifications and decreased RBC deformability. However, endogenously, and exogenously generated NO protects RBC membrane flexibility from further oxidative modification by shielding redox-sensitive cysteine residues with a glutathione cap. Recent studies have shown that nitrate-rich diets and moderate exercise can enhance NO production to increase RBC deformability by increasing the interplay between RBCs and vascular endothelium-mediated NO bioavailability for microcirculation. This review focuses on the molecular mechanism of RBC- and non-RBC-mediated NO generation, and how diet- and exercise-derived NO exert prophylactic effects against decreased RBC deformability in lifestyle-related diseases with vascular endothelial dysfunction.

The aim of this study was to evaluate the characterized hydration method to prepare nanoparticles using Soluplus, a block copolymer with amphipathic properties, and distearoyl phosphatidyl ethanolamine (DSPE)-PEG2000 owing to particle size distribution, zeta potential, particle stability, and transmission electron microscopy (TEM) observed and ³¹P-NMR spectra. The results showed that, in a suspension of DSPE-PEG2000 and Soluplus at a ratio of 1/1, the prepared microparticles were stable for five days in the dark and at 25 °C. It was also confirmed that the 1/1 suspension of DSPE-PEG2000/Soluplus was stable for five days under the same conditions with the magnesium chloride solution. TEM measurements confirmed the presence of micelle-like particles of 50 to 150 nm in the 1/1 ratio mix of DSPE-PEG2000/Soluplus. ³¹P-NMR spectral data confirmed that DPSE-PEG2000/Soluplus at mixing ratio of 1/1 has a strong intermolecular with the phosphate group, indicated by the fact that the peak shift and the full width at half maximum were the largest compared with DSPE-PEG2000 with the intermolecular interaction. On the basis of the findings of this study, we conclude that microparticles can be formed using DSPE-PEG2000 and Soluplus via the hydration method, and that the optimum weight ratio of DSPE-PEG2000 to Soluplus is 1/1.

Crush syndrome (CS) is a potentially lethal condition characterized by muscle cell damage resulting from decompression following compression. Patients with CS can develop cardiac failure, kidney dysfunction, shock, systemic inflammation and sepsis. Salvianolic acid B (SalB) has cardiac and kidney protective effects and anti‑oxidative, anti‑inflammatory, anti‑apoptotic and anti‑bacterial properties. The present study aimed to demonstrate the survival benefit of SalB in the CS rat model, which comprised anesthetized rats with bilateral hindlimb compression by a rubber tourniquet for 5 h. The rats examined were randomly divided into four groups: i) Sham; ii) sham treated with SalB; iii) CS rat model without treatment; and iv) CS rat model treated with SalB. Under continuous monitoring and recording of arterial blood pressures, blood and tissue samples were collected for biochemical analyses at designated timepoints before and after reperfusion. SalB administration improved the survival rate, kidney function (by treating shock and metabolic acidosis) and inflammation (by reducing mitochondrial dysfunction and endothelial damage). Reduced incidence of cardiac failure due to hyperkalemia was associated with reduced muscle injury via the prevention of mitochondrial dysfunction. Additionally, indirect antibacterial action by the neutrophil extracellular trap system (NETs) was observed. SalB administration to the CS rat model led to a substantial improvement in survival following CS by decreasing kidney and cardiac dysfunctions, inflammation, and endothelial dysfunction by improving the mitochondrial function and through antibacterial effects via NETs.