The Prevention of Ischemia-Reperfusion Injury in Elderly Rats after Lower Limb Tourniquet Use

Effect of peripheral blood mononuclear cells on ischemia-reperfusion injury of sciatic nerve of adult male albino rat: histological, immunohistochemical, and ultrastructural study

Ischemia/reperfusion (I/R) injury of sciatic nerve is a serious condition that results in nerve fiber degeneration, and reperfusion causes oxidative injury. Peripheral blood mononuclear cells (PBMNCs) have neuroregenerative power. This study was carried out to evaluate the potential ameliorative effect of PBMNCs on changes induced by I/R injury of the sciatic nerve. Fifty adult male albino rats were divided into donor and experimental groups that were subdivided into four groups: group I (control group), group II received 50 µL PBNMCs once intravenously via the tail vein, group III rubber tourniquet was placed around their Rt hind limb root for 2 hours to cause ischemia, group IV was subjected to limb ischemia as group III, then they were injected with 50 ul PBMNCs as group II before reperfusion. I/R injury showed disorganization of nerve fascicles with wide spaces in between nerve fibers. The mean area of collagen fibers, iNOS immunoexpression, and number of GFAP-positive Schwann cells of myelinated fibers showed a highly significant increase, while a highly significant reduction in the G-ratio and neurofilament immunoexpression was observed. Myelin splitting, invagination, evagination, and myelin figures were detected. PBMNC-treated group showed a marked improvement that was confirmed by histological, immunohistochemical, and ultrastructural findings.

Effect of fullerenol C60 on lung and renal tissue in lower extremity ischemia‑reperfusion injury in sevoflurane‑treated rats

The aim of the present study was to examine the effect of fullerenol C60 on lung and kidney tissue in sevoflurane‑treated rats with lower extremity ischemia‑reperfusion (IR) injury. A total of 30 Wistar albino rats weighing 225‑275 g were used and were equally divided into five groups (n=6/group): i) Sham; ii) IR; iii) IR‑fullerenol C60 (IR‑FUL); iv) IR‑sevoflurane; and v) IR‑fullerenol C60‑sevoflurane (IR‑FUL‑SEVO). Fullerenol C60 was administered intraperitoneally prior to lower extremity IR induction and sevoflurane was administered during the IR injury. Subsequently, lung and kidney histopathological examinations, and serum biochemical analyses were performed. Lung tissue showed markedly increased congestion and neutrophil infiltration in the IR group compared with in the sham group, and notable decreases in congestion and neutrophil infiltration were observed in the treatment groups compared with in the IR group. In the histopathological evaluation of the kidney samples, vacuolization, loss of brush border in tubular epithelial cells, tubular epithelial loss and varying degrees of tubular damage were observed in all groups that underwent IR. There was a significant increase in the mean renal tubule injury score in all IR groups compared with that in the sham group. In addition, the mean kidney injury score was significantly lower in the IR‑FUL and IR‑FUL‑SEVO groups than that in the IR group. It was observed that the expression levels of tumor necrosis factor‑α, interleukin 1β and intercellular adhesion molecule 1 in the lung and kidney tissues were increased following IR, and were decreased in the groups treated with fullerenol C60 and sevoflurane. Notably, it was determined that the reduction in cytokine expression was greatest in the IR‑FUL group. When the oxidant status parameters in the lungs and kidneys were examined, thiobarbituric acid reactive substances levels, and catalase and glutathione S‑transferase enzyme activities were significantly different in the groups receiving sevoflurane or fullerenol C60 treatment compared with those in the IR group. The present study demonstrated the protective effects of fullerenol C60 on the lung and kidney tissues of rats under sevoflurane anesthesia after establishment of lower extremity IR. The results of the present study showed that fullerenol C60 can reduce oxidative and histopathological damage in the lungs and kidneys following IR of the lower extremities.

DNase I and Sivelestat Ameliorate Experimental Hindlimb Ischemia-Reperfusion Injury by Eliminating Neutrophil Extracellular Traps

Purpose

Neutrophil extracellular traps (NETs) play an important role in ischemia-reperfusion injury (IRI) of the hindlimb. The aim of this study was to investigate the effect of recombinant DNase I and sivelestat in eliminating NETs and their effects on IRI limbs.

Patients and Methods

An air pump was used to apply a pressure of 300 mmHg to the root of the right hindlimb of the rat for 2 h and then deflated to replicate the IRI model. The formation of NETs was determined by the detection of myeloperoxidase (MPO), neutrophil elastase (NE), and histone H3 in the skeletal muscles of the hindlimbs. Animals were administered 2.5 mg/kg bw/d DNase I, 15 or 60 mg/kg bw/d sivelestat by injection into the tail vein or intramuscularly into the ischemic area for 7d. Elimination of NETs, hindlimb perfusion, muscle fibrosis, angiogenesis and motor function were assessed.

Results

DNase I reduced NETs, attenuated muscle fibrosis, promoted angiogenesis in IRI area and improved limb motor function. Local administration of DNase I improved hindlimb perfusion more than intravenous administration. Sivelestat at a dose of 15 mg/kg bw/d increased perfusion, counteracted skeletal muscle fibrosis, promoted angiogenesis and enhanced motor function. However, sivelestat at a dosage of 60 mg/kg bw/d had an adverse effect on tissue repair, especially when injected locally.

Conclusion

Both DNase I and moderate doses of sivelestat can eliminate IRI-derived NETs. They improve hindlimb function by improving perfusion and angiogenesis, preventing muscle fibrosis. Appropriate administration mode and dosage is the key to prevent IRI by elimination of NETs. DNase I is more valid when administered topically and sivelestat is more effective when administered intravenously. These results will provide a better strategy for the treatment of IRI in clinical.