The protective effects of ischemic preconditioning on rats with renal ischemia-reperfusion injury and the effects on the expression of Bcl-2 and Bax

The potential renoprotective effect of Raloxifene in renal ischemia-reperfusion injury in a male rat model

Renal ischemia-reperfusion injury is caused by a temporary reduction in oxygen-carrying blood flow to the kidney, followed by reperfusion. During ischemia, kidney tissue damage induces overproduction of reactive oxygen species, which produces oxidative stress. The blood flow restoration during the reperfusion period causes further production of reactive oxygen species that ends with apoptosis and cell death. This study aimed to investigate the potential renoprotective effects of Raloxifene on bilateral renal ischemia-reperfusion injury in rats by looking into kidney function biomarkers, urea and creatinine, inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1β). Additionally, antioxidant markers such as total antioxidant capacity (TAC) and the pro-apoptotic marker caspase-3 were assessed. Histopathological scores were also employed for evaluation. Our experimental design involved 20 rats divided into four groups: the sham group underwent median laparotomy without ischemia induction, the control group experienced bilateral renal ischemia for 30 minutes followed by 2 hours of reperfusion, the vehicle group received pretreatment with a mixture of corn oil and dimethyl sulfoxide (DMSO) before ischemia induction, and the Raloxifene-treated group was administered Raloxifene at a dose of 10 mg/kg before ischemia induction, followed by ischemia-reperfusion. Urea and creatinine, TNF-α, IL-1β, and caspase-3 in the Raloxifene group were significantly lower compared to the control and vehicle groups. On the other hand, TAC levels in the Raloxifene group were significantly higher than in the control and vehicle groups. This study concluded that Raloxifene had a renoprotective impact via multiple actions as an anti-inflammatory, anti-apoptotic, and antioxidant agent.

THE POTENTIAL RENOPROTECTIVE EFFECT OF TILIANIN IN RENAL ISCHEMIA REPERFUSION INJURY IN MALE RAT MODEL

OBJECTIVE

The aim: To determine whether Tilianin (TIL) may have Nephroprotective effects on bilateral renal IRI in rats by analyzing kidney function biomarkers U and Cr, inflammatory cytokines like TNF α and IL-1β, antioxidant marker total anti-oxidant Capacity (TAC), anti-apoptotic markers caspase-3, and histopathological scores.

PATIENTS AND METHODS

Materials and methods: 20 rats divided into even 4 groups as: Sham group: Rats underwent median laparotomies without having their ischemia induced. Control group: Rats had bilateral renal ischemia for 30 minutes, followed by 2 hours of reperfusion. Vehicle group: 30 minutes prior to the onset of ischemia, rats were given a pretreatment of corn oil and DMSO. Tilianin treated group: Rats administered Tilianin 5 mg/kg for 30 min prior to ischemia induction, then IRI.

RESULTS

Results: The study found that the serum levels of TNF, IL-1, caspase-3, urea and creatinine, as well as TNF and creatinine in the Tilianin group were significantly lower than those of the control and vehicle groups. On the other hand, it revealed that TAC levels are remarkably higher in the Tilianin group than they are in the control and vehicle groups.

CONCLUSION

Conclusions: This study concluded that Tilianin have a Nephroprotective effect via multiple impacts as anti-inflammatory, anti-apoptotic, and anti-oxidant agents.

Size-Dependent Cytoprotective Effects of Selenium Nanoparticles during Oxygen-Glucose Deprivation in Brain Cortical Cells

It is known that selenium nanoparticles (SeNPs) obtained on their basis have a pleiotropic effect, inducing the process of apoptosis in tumor cells, on the one hand, and protecting healthy tissue cells from death under stress, on the other hand. It has been established that SeNPs protect brain cells from ischemia/reoxygenation through activation of the Ca2+ signaling system of astrocytes and reactive astrogliosis. At the same time, for a number of particles, the limitations of their use, associated with their size, are shown. The use of nanoparticles with a diameter of less than 10 nm leads to their short life-time in the bloodstream and rapid removal by the liver. Nanoparticles larger than 200 nm activate the complement system and are also quickly removed from the blood. The effects of different-sized SeNPs on brain cells have hardly been studied. Using the laser ablation method, we obtained SeNPs of various diameters: 50 nm, 100 nm, and 400 nm. Using fluorescence microscopy, vitality tests, PCR analysis, and immunocytochemistry, it was shown that all three types of the different-sized SeNPs have a cytoprotective effect on brain cortex cells under conditions of oxygen-glucose deprivation (OGD) and reoxygenation (R), suppressing the processes of necrotic death and inhibiting different efficiency processes of apoptosis. All of the studied SeNPs activate the Ca2+ signaling system of astrocytes, while simultaneously inducing different types of Ca2+ signals. SeNPs sized at 50 nm- induce Ca2+ responses of astrocytes in the form of a gradual irreversible increase in the concentration of cytosolic Ca2+ ([Ca2+]i), 100 nm-sized SeNPs induce stable Ca2+ oscillations without increasing the base level of [Ca2+]i, and 400 nm-sized SeNPs cause mixed patterns of Ca2+ signals. Such differences in the level of astrocyte Ca2+ signaling can explain the different cytoprotective efficacy of SeNPs, which is expressed in the expression of protective proteins and the activation of reactive astrogliosis. In terms of the cytoprotective efficiency under OGD/R conditions, different-sized SeNPs can be arranged in descending order: 100 nm-sized > 400 nm-sized > 50 nm-sized.

Detection of Kidney Dysfunction through In Vivo Magnetic Resonance Imaging with Renal-Clearable Gadolinium Nanoprobes

Kidney dysfunction is a clinical syndrome that can subsequently result in lethal kidney failure. The exploration of emerging bioimaging contrast agents with translational potential is highly challenging for a feasible diagnosis of kidney dysfunction. Herein, a class of renal-clearable gadolinium nanoparticles (Gd@PEG NPs) with an ultrasmall size of ∼5 nm, good monodispersity, and T₁ relaxivity are synthesized using mesoporous silica nanoparticles as the template. Assisted by such renal-clearable Gd@PEG NPs, the diagnosis of kidney dysfunction in a mice model with a damaged kidney has been achieved through in vivo noninvasive magnetic resonance imaging. As a result, this work paves the way to synthesize monodispersible ultrasmall Gd contrast agents, facilitating the exploration of translational strategies for an in vivo analysis of kidney dysfunction.

microRNA-130a-5p suppresses myocardial ischemia reperfusion injury by downregulating the HMGB2/NF-κB axis

BACKGROUND

Myocardial ischemia reperfusion injury (MIRI) is defined as tissue injury in the pathological process of progressive aggravation in ischemic myocardium after the occurrence of acute coronary artery occlusion. Research has documented the involvement of microRNAs (miRs) in MIRI. However, there is obscure information about the role of miR-130a-5p in MIRI. Herein, this study aims to investigate the effect of miR-130a-5p on MIRI.

METHODS

MIRI mouse models were established. Then, the cardiac function and hemodynamics were detected using ultrasonography and multiconductive physiological recorder. Functional assays in miR-130a-5p were adopted to test the degrees of oxidative stress, mitochondrial functions, inflammation and apoptosis. Hematoxylin and eosin (HE) staining was performed to validate the myocardial injury in mice. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) was employed to assess the expression patterns of miR-130a-5p, high mobility group box (HMGB)2 and NF-κB. Then, dual-luciferase reporter gene assay was performed to elucidate the targeting relation between miR-130a-5p and HMGB2.

RESULTS

Disrupted structural arrangement in MIRI mouse models was evident from HE staining. RT-qPCR revealed that overexpressed miR-130a-5p alleviated MIRI, MIRI-induced oxidative stress and mitochondrial disorder in the mice. Next, the targeting relation between miR-130a-5p and HMGB2 was ascertained. Overexpressed HMGB2 annulled the protective effects of miR-130a-5p in MIRI mice. Additionally, miR-130a-5p targets HMGB2 to downregulate the nuclear factor kappa-B (NF-κB) axis, mitigating the inflammatory injury induced by MIRI.

CONCLUSION

Our study demonstrated that miR-130a-5p suppresses MIRI by down-regulating the HMGB2/NF-κB axis. This investigation may provide novel insights for development of MIRI treatments.

Upregulation of antioxidant nuclear factor erythroid 2-related factor 2 and its dependent genes associated with enhancing renal ischemic preconditioning renoprotection using levosimendan and cilostazol in an ischemia/reperfusion rat model

INTRODUCTION

Ischemic preconditioning (Ipre) provides protection against renal ischemia-reperfusion (I/R) injury with its associated remote organ damage. This study examined the enhancing protective effect of Ipre with levosimendan or cilostazol in I/R-induced kidney and lung injury in a rat model.

MATERIAL AND METHODS

Rats were divided into: sham-operated, I/R control, Ipre control, I/R + cilostazol or levosimendan and Ipre + cilostazol or levosimendan. Drugs were given 30 min before left renal I/R or 4 cycles of Ipre just before renal ischemia.

RESULTS

The Ipre combined with the implemented drugs enhanced physiological antioxidant defense genes including renal nuclear factor erythroid 2-related factor 2 (Nrf2) and its dependent genes heme oxygenase-1 (HO-1) and NADPH-quinone oxidoreductase-1 (NQO-1) and improved malondialdehyde and superoxide dismutase renal tissue levels. The combined effect improved I/R consequences for blood urea, creatinine, and creatinine clearance and improved blood oxygenation and metabolic acidosis. Moreover, the combination improved the renal soluble intercellular adhesion molecule (ICAM), tumor necrosis factor α (TNF-α) and interlukin-6 (IL-6) with histopathological improvement of tubular necrosis with a decrease in the apoptotic marker caspase-3 and an increase in the anti-apoptotic Bcl-2 expression.

CONCLUSIONS

Cilostazol or levosimendan potentiates the renoprotective effect of Ipre against renal I/R injury, associated with upregulation of antioxidant genes Nrf2, HO-1, and NOQ-1 expression.

Mechanisms and therapeutic targets of ischemic acute kidney injury

Acute kidney injury (AKI) due to renal ischemia reperfusion (IR) is a major clinical problem without effective therapy and is a significant and frequent cause of morbidity and mortality during the perioperative period. Although the pathophysiology of ischemic AKI is not completely understood, several important mechanisms of renal IR-induced AKI have been studied. Renal ischemia and subsequent reperfusion injury initiates signaling cascades mediating renal cell necrosis, apoptosis, and inflammation, leading to AKI. Better understanding of the molecular and cellular pathophysiological mechanisms underlying ischemic AKI will provide more targeted approach to prevent and treat renal IR injury. In this review, we summarize important mechanisms of ischemic AKI, including renal cell death pathways and the contribution of endothelial cells, epithelial cells, and leukocytes to the inflammatory response during ischemic AKI. Additionally, we provide some updated potential therapeutic targets for the prevention or treatment of ischemic AKI, including Toll-like receptors, adenosine receptors, and peptidylarginine deiminase 4. Finally, we propose mechanisms of ischemic AKI-induced liver, intestine, and kidney dysfunction and systemic inflammation mainly mediated by Paneth cell degranulation as a potential explanation for the high mortality observed with AKI.

The Effects of Meldonium on the Renal Acute Ischemia/Reperfusion Injury in Rats

Acute renal ischemia/reperfusion (I/R) injury is a clinical condition that is challenging to treat. Meldonium is an anti-ischemic agent that shifts energy production from fatty acid oxidation to less oxygen-consuming glycolysis. Thus, in this study we investigated the effects of a four-week meldonium pre-treatment (300 mg/kg b.m./day) on acute renal I/R in male rats (Wistar strain). Our results showed that meldonium decreased animal body mass gain, food and water intake, and carnitine, glucose, and lactic acid kidney content. In kidneys of animals subjected to I/R, meldonium increased phosphorylation of mitogen-activated protein kinase p38 and protein kinase B, and increased the expression of nuclear factor erythroid 2-related factor 2 and haeme oxygenase 1, causing manganese superoxide dismutase expression and activity to increase, as well as lipid peroxidation, cooper-zinc superoxide dismutase, glutathione peroxidase, and glutathione reductase activities to decrease. By decreasing the kidney Bax/Bcl2 expression ratio and kidney and serum high mobility group box 1 protein content, meldonium reduced apoptotic and necrotic events in I/R, as confirmed by kidney histology. Meldonium increased adrenal noradrenaline content and serum, adrenal, hepatic, and renal ascorbic/dehydroascorbic acid ratio, which caused complex changes in renal lipidomics. Taken together, our results have confirmed that meldonium pre-treatment protects against I/R-induced oxidative stress and apoptosis/necrosis.

Acute remote ischemic preconditioning alleviates free radical injury and inflammatory response in cerebral ischemia/reperfusion rats

Remote ischemic preconditioning (IPreC) is an effective strategy to defend against cerebral ischemia/reperfusion (IR) injury; however, its mechanisms remain to be elucidated. The aim of the present study was to investigate the effect of IPreC on brain tissue following cerebral ischemia, as well as the underlying mechanisms. Adult male Sprague-Dawley rats were treated with IPreC for 72 h prior to the induction of transient cerebral ischemia and reperfusion. The results demonstrated that IPreC reduced the area of cerebral infarction in the IR rats by 2,3,5-triphenyl-tetrazolium chloride staining. In addition, cell apoptosis was markedly suppressed by IPreC with an increased expression of B-cell lymphoma 2 (Bcl-2)/Bcl-2-associatd X protein using Terminal deoxynucleotidyl-transferase-mediated dUTP nick end labeling assay and western blot analysis. IR induced a decrease in the level of superoxide dismutase, and IPreC significantly suppressed increased levels of malondialdehyde, lactate dehydrogenase and nitric oxide. The expression of CD11b and CD18 was markedly inhibited by IpreC unsing flow cytometry. Furthermore, IPreC markedly decreased the release of pro-inflammatory factors interleukin (IL)-6 and IL-1β, and enhanced the level of anti-inflammatory factors (IL-10 and IL-1 receptor antagonist) by ELISA assay. Finally, IPreC reduced the levels of transforming growth factor-β-activated kinase 1, phosphorylated-P65/P65, and tumor necrosis factor-α, indicating that the nuclear factor-κB pathway was involved in IPreC-mediated protection against cerebral ischemia. Taken together, the results suggested that IPreC decreased ischemic brain injury through alleviating free radical injury and the inflammatory response in cerebral IR rats.

Therapeutic effect of berberine on renal ischemia-reperfusion injury in rats and its effect on Bax and Bcl-2

This study aimed to investigate the therapeutic effect of berberine on renal ischemia-reperfusion injury in rats and its effect on Bax and Bcl-2. Sixty adult SD rats were randomly divided into four groups: control group A, renal ischemia-reperfusion group B, berberine group C and berberine + exendin-(9-39) treatment group D. In group A, right kidney was resected and left renal pedicle was separated, but left renal artery was not blocked. Renal ischemia-reperfusion model was established in other groups. Rats in group C were not subjected to any treatment after model construction. Rats in group C and D were subjected to intraperitoneal injection of berberine 7 days before the experiment. Besides that, intraperitoneal injection of exendin-(9-39) was performed at day 1 and 4 after model construction. Automatic biochemical analyzer was used to measure serum creatinine (SCr) and blood urea nitrogen (BUN). Malondialdehyde (MDA) in renal cortex was measured by enzyme-linked immunosorbent assay and contents of Bax and Bcl-2 in renal tissue were measured by western blot analysis. Apoptosis of rat renal cells was detected by TUNEL assay. The results showed that levels of SCr, BUN, MDA and Bax were significantly higher in group B than in other groups (P<0.05). Levels of Bcl-2 in group B were significantly higher than those in group A but significantly lower than those in group C and D. Compared with group A, apoptosis of renal cells was more severe in group B. Compared with group B, apoptosis of renal cells was significantly improved in group C and D, but was still more severe than that in group A. In conclusion, berberine can effectively improve renal function in rats with renal ischemia-reperfusion injury by inhibiting Bax expression and promoting Bcl-2 expression.