Intravenous pretreatment with emulsified isoflurane preconditioning protects kidneys against ischemia/reperfusion injury in rats

Effect of Metformin on Myocardial Injury Induced by Hepatic Ischemia-Reperfusion in Rats

Background: There is no effective medication for treatment or prevention of hepatic ischemia-reperfusion (HIR) injury caused by liver transplantation and hepatectomy. This study aimed to investigate the therapeutic effects of metformin on HIR injury and related myocardial injury in rats.

Methods: Wistar male rats were randomly divided into four groups: sham group, ischemia-reperfusion group, and IR group treated with metformin 150 mg/kg and 100 mg/kg. Wistar male rats were administered metformin 150 mg/kg, 100 mg/kg or saline 30 min pre-operative and underwent 15 min ischemia and 6 h reperfusion (n = 4).

Results: Metformin significantly alleviates the injury caused by HIR. Administration of metformin resulted in a significant reduction in the serum levels of alanine transaminase and aspartate transaminase and the activity of malondialdehyde, creatine kinase-MB, and lactate dehydrogenase but maintained high catalase and superoxide dismutase activity. Metformin significantly inhibited the IR-induced elevation of tumor necrosis factor-α in liver and heart tissue.

Conclusion: Metformin can alleviate hepatic and myocardial injury induced by IR by inhibiting oxidative stress.

Isoflurane upregulates microRNA-9-3p to protect rats from hepatic ischemia-reperfusion injury through inhibiting fibronectin type III domain containing 3B

Isoflurane has been studied in ischemia-reperfusion injury, while the regulatory mechanism by which isoflurane regulates microRNA(miR)-9-3p in hepatic ischemia/reperfusion injury (HIRI) via targeting fibronectin type III domain containing 3B (FNDC3B) remains seldom investigated. This study aims to determine the role of miR-9-3p in HIRI progression under the treatment of isoflurane. Rat HIRI models were established and treated with isoflurane. MiR-9-3p was altered to assess its role in inflammation, oxidative stress, transaminases, pathology, and hepatocyte apoptosis in HIRI rat liver tissues. Expression of miR-9-3p and FNDC3B in rat liver tissues was determined, and the targeting relationship between miR-9-3p and FNDC3B was confirmed using bioinformatic prediction and dual luciferase reporter gene assay. MiR-9-3p was downregulated, whereas FNDC3B was upregulated in HIRI rat liver tissues. Isoflurane treatment upregulated miR-9-3p and attenuated pathological changes, inflammation, oxidative stress, transaminases, and hepatocyte apoptosis in HIRI rat liver tissues. MiR-9-3p upregulation further strengthened the effect of isoflurane on HIRI, while miR-9-3p downregulation suppressed the therapeutic role of isoflurane. FNDC3B was confirmed as a target gene of miR-9-3p. Isoflurane upregulates miR-9-3p to protect rats from HIRI by inhibiting FNDC3VB. Our research may provide novel targets for HIRI treatment.

MicroRNA-21 mediates the protective role of emulsified isoflurane against myocardial ischemia/reperfusion injury in mice by targeting SPP1

Isoflurane has demonstrated to exert protective impacts against ischemia/reperfusion (I/R) injury in some organs. This research explored the role of emulsified isoflurane (EI) in myocardial I/R injury through the interaction with microRNA-21 (miR-21). The myocardial I/R injury mouse models established by coronary artery ligation were respectively treated with EI, miR-21 mimic/inhibitor or silenced secreted phosphoprotein 1 (SPP1) plasmids. Then, the pathology, fibrosis and cardiomyocyte apoptosis in mouse myocardial tissues were observed. Furthermore, the expression levels of miR-21, SPP1, oxidative stress indices, inflammatory factors and apoptotic proteins in mouse myocardial tissues were determined. The targeting relation between miR-21 and SPP1 was confirmed. MiR-21 was poorly expressed and SPP1 was highly expressed in myocardial I/R injury mice. EI treatment, elevated miR-21, or silenced SPP1 improved cardiac function and suppressed the oxidative stress, myocardial fibrosis, inflammatory reaction and cardiomyocyte apoptosis in myocardial I/R injury mice, thereby reliving the myocardial I/R injury. These therapeutic effects of EI were repressed by miR-21 inhibition. Additionally, SPP1 was targeted by miR-21. Results in our research indicated that miR-21 mediated the therapeutic effect of EI on myocardial I/R injury in mice by targeting SPP1. This study may provide a novel treatment strategy for myocardial I/R injury.

Isoflurane Increases Tolerance to Renal Ischemia Reperfusion Injury Compared to Propofol: An Experimental Study in Pigs

Purpose: To compare two clinically relevant anesthetic agents, i.e., isoflurane versus propofol with respect to protection of the kidney in a porcine renal ischemia reperfusion model. Materials and Methods: 14 hybrid pigs were randomized to anesthesia with either isoflurane or propofol prior to laparoscopic surgery. Following anesthesia, the left kidney hilum was clamped for 60 min and the right kidney removed. After 48 h of reperfusion, urine was sampled for analysis of neutrophil gelatinase-associated lipocalin (NGAL), albumin, and creatinine. The left kidney was harvested for histologic scoring of injury. Results: Histologic examination of renal injury revealed a statistically significant difference in favor of isoflurane on denuded basement membrane score (isoflurane group 1.58 ± 0.38 vs. propofol 2.42 ± 0.80, p = .026). Median (25-75 percentile) urinary albumin 3.4 g/L (2.25-7.48) vs. 8.9 g/L (3.73-13.8), (p = .041) and urinary albumin/creatinine ratio 1.17 (0.76-1.82) vs. 1.76 (1.63-5.99), (p = .026) were both significantly lower in the isoflurane group. Median (25-75 percentile) urinary NGAL was 167 (51-215) pg/ml in the isoflurane group compared with 362 (149-508) pg/ml in the propofol group (p = .093). Conclusion: Isoflurane increases tolerance to renal ischemia reperfusion injury compared to propofol in this model.

Isoflurane Preconditioning Attenuates Brain Injury Induced by Electromagnetic Pulse via the TLR4/NFκB Signaling Pathway

Electromagnetic pulse (EMP) is a unique type of electromagnetic radiation, and EMP exposure causes a series of biological effects. The nervous system is sensitive to EMP. We studied the neuroprotective effects of isoflurane preconditioning against EMP exposure and used hematoxylin-eosin staining (HE) to observe the effects of electromagnetic pulse and isoflurane preconditioning on neurons. Inflammatory cytokines were detected by enzyme-linked immunosorbent assay (ELISA). Western blotting was used to detect the expression of caspase-3, CD11b, TLR4, and NFκBp65. We found that after EMP exposure, the number of abnormal neurons had increased, and the expression of caspase-3, CD11b, TLR4, and NFκBp65 had also increased. Isoflurane preconditioning can reverse the above phenomenon. Moreover, we found that isoflurane preconditioning can reduce neuronal apoptosis and improve cognitive impairment induced by EMP. These findings indicate that isoflurane preconditioning can protect neurons in the cerebral cortex from EMP exposure, alleviate the inflammatory reaction and cell apoptosis, and improve cognitive impairment induced by EMP. These effects may occur through the downregulation of the TLR4/NFκB signaling pathway and the inhibition of microglial activation.

Emulsified isoflurane postconditioning improves survival and neurological outcomes in a rat model of cardiac arrest

Emulsified isoflurane (EIso) has a protective effect against ischemia/reperfusion (I/R) injury in animal models. However, the protective effects of EIso on global cerebral I/R injury remain unclear. The present study aimed to investigate whether EIso postconditioning was able to improve survival and neurological outcomes in a rat model of cardiac arrest (CA). Rats were randomly divided into five groups, namely the control, EIso-2ml, EIso-4ml, isoflurane (Iso) and emulsion (E) groups. All rats were resuscitated by a standardized method following 6 min of asphyxia. Furthermore, all interventions were administered immediately following the return of spontaneous circulation (ROSC). The animal survival was recorded daily, and evaluations of behavioral and brain morphology were assessed at 1 and 7 days after ROSC. The results showed that EIso treatment increased the survival rate 7 days after ROSC, with a 41.7% 7-day survival in the EIso-2ml group, 66.7% in the EIso-4ml group and 50% in the Iso group compared with 33.3% survival in the control and E groups. Moreover, the neural deficit score and memory function were improved in the EIso-4ml group, and this treatment also ameliorated brain hippocampal cell injury and apoptosis. In addition, a better brain protective effect was observed in the EIso-4ml group compared with the EIso-2ml, Iso and E groups. In summary, the data of the present study suggest that EIso postconditioning improved the survival and neurological outcomes following CA in a dose-dependent manner.

Emulsified isoflurane combined with therapeutic hypothermia improves survival and neurological outcomes in a rat model of cardiac arrest

Emulsified isoflurane (EIso), when introduced following cardiopulmonary resuscitation (CPR), significantly improves survival and neurological outcomes in a rat model of cardiac arrest (CA). The present study aimed to examine whether EIso combined with therapeutic hypothermia (TH) confers an additive neuroprotective effect. Adult male Sprague-Dawley rats that were subjected to return of spontaneous circulation (ROSC) after a 6-min asphyxia-induced CA were randomized to five groups: Sham group, control group under normothermic conditions, EIso group (4 ml/kg for 30 min under normothermic conditions), TH group (33°C for 2 h), and EIso plus TH group. Survival conditions and neurological outcomes were evaluated at 1 day and 7 days after ROSC. Animal survival rate at 7 days after ROSC was 30.7% in the CPR group, 60% in the EIso group, 63.6% in the TH group and 72.7% in the EIso plus TH group. EIso, TH and EIso plus TH yielded significant improvements in survival rates, neural deficit score and cognitive function, and ameliorated hippocampal CA1 region cell injury and apoptosis at 1 day and 7 days after ROSC compared with the CPR group. Combined therapy of EIso and TH was superior to EIso or TH alone, suggesting that combined EIso and TH treatment results in significant improvements in survival and neurological outcomes, and was more effective than independent EIso or TH treatment.

Emulsified isoflurane treatment inhibits the cell cycle and respiration of human bronchial epithelial 16HBE cells in a p53-independent manner

Emulsified isoflurane (EIso), as a result of its rapid anesthetic induction, recovery and convenience, is widely used as a novel intravenous general anesthetic. Treatment with EIso can reduce injuries caused by ischemia/reperfusion (I/R) to organs, including the heart, lung and liver, without knowing understanding the molecular mechanism. The present study hypothesized that treatment with EIso can affect the physiological processes of human lung bronchial epithelial cells (16HBE) prior to I/R. To test this hypothesis, the present study first constructed stable p53 knockdown and synthesis of cytochrome c oxidase (SCO)2 knockdown 16HBE cells. The above cells were subsequently treated with EIso at a concentration of 0.1 and 0.2% for 24 h. The relevant concentration of fat emulsion was used as a negative control. The expression levels of p53, p21, SCO1, SCO2 and Tp53‑induced glycolysis and apoptosis regulator (TIGAR) were detected by reverse transcription‑quantitative polymerase chain reaction and western blotting. Subsequently, the cell proliferation, respiration and glycolysis were investigated. The results revealed that EIso treatment significantly decreased the transcription of TIGAR, SCO1 and SCO2, and increased the transcription of p21, which are all p53 target genes, in a p53-independent manner. The cell cycle was inhibited by arresting cells at the G0/G1 phase. Respiration was reduced, which caused a decrease in oxygen consumption and the accumulation of lactate and reactive oxygen species. Taken together, EIso treatment inhibited the proliferation and respiration, and promoted glycolysis in 16HBE cells. This regulatory pathway may represent a protective mechanism of EIso treatment by inhibiting cell growth and decreasing the oxygen consumption from I/R.

Remote Ischemic Preconditioning May Attenuate Renal Ischemia-Reperfusion Injury in a Porcine Model of Supraceliac Aortic Cross-Clamping

AIM

The effect of remote ischemic preconditioning (RIPC) in decreasing renal ischemia-reperfusion injury (IRI) during a suprarenal aortic cross-clamping was examined in a swine model.

MATERIALS AND METHODS

Four groups of pigs were examined: (a) ischemia-reperfusion (IR) group, renal IRI produced by 30 min of supraceliac aortic cross-clamping; (b) RIPC I group, the same renal IRI following RIPC by brief occlusion of the infrarenal aorta (15 min ischemia and 15 min reperfusion); (c) RIPC II group, the same renal IRI following RIPC by brief occlusion of the infrarenal aorta (3 cycles of 5 min ischemia and 5 min reperfusion); (d) sham group. Renal function was assessed before and after IRI by examining creatinine, neutrophil gelatinase-associated lipocalin (NGAL), TNF-α, malondialdehyde (MDA), cystatin C and C-reactive protein (CRP) from renal vein blood samples at specific time intervals.

RESULTS

Both RIPC groups presented significantly less impaired results compared to the IR group when considering MDA, cystatin C, CRP and creatinine. Between the two RIPC groups, RIPC II presented a better response with regard to CRP, NGAL, TNF-α, MDA and cystatin C.

CONCLUSIONS

Remote IR protocols and mainly repetitive short periods of cycles of IR ameliorate the biochemical kidney effects of IRI in a model of suprarenal aortic aneurysm repair.

Catalpol protects mice against renal ischemia/reperfusion injury via suppressing PI3K/Akt-eNOS signaling and inflammation

Renal ischemia/reperfusion-injury (IRI) is a common disease in clinic, which is also the most common cause of acute kidney failure. Previous investigations has illustrated that catalpol has neuroprotective, anti-inflammatory, and anti-hepatitis virus effects. This study was designed to investigate the protective effect of catalpol on renal IRI mice through suppressing phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt)-endothelial nitric oxide synthase (eNOS) and against inflammation, and the possible underlying mechanism. Firstly, we used renal IRI model to analyze blood urea nitrogen and serum creatinine levels in renal IRI mice. Next, real-time PCR and western blotting were used to detect the expression of KIM-1 and the expression of PI3K, Akt and eNOS levels in renal IRI, respectively. In addition, activities of tumor necrosis factor α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6) and interleukin-10 (IL-10) in renal IRI mice were measured with respective TNF-α, IL-1β, IL-6 and IL-10 ELISA kits. Our results showed that catalpol clearly reduced blood urea nitrogen, serum creatinine levels and the expression of KIM-1 in renal IRI mice. Meanwhile, we found that catalpol markedly reduced the expression of PI3K, Akt and eNOS levels in renal IRI group. Suppressing of the PI3K/Akt-eNOS and the TNF-α, IL-1β, IL-6 and IL-10 activities was involved in the protective effect of catalpol on renal IRI. Collectively, catalpol protected renal IRI via inhibiting PI3K/Akt-eNOS signaling and inflammatory responses.