Glycerol-induced Acute Kidney Injury Research Articles

Protection Effect of Soy Isoflavones (Genistein and Daidzein) on Hematologic Parameters in Acute Kidney Injury

Background: Acute kidney injury (AKI) is a severe, high-morbidity condition with limited effective preventative and therapeutic strategies despite advancements in understanding and treatment. Specific Background: Rhabdomyolysis-induced acute kidney injury (AKI) presents significant challenges in renal research, but soy isoflavones, particularly GN and DZ, have shown potential in mitigating oxidative stress and inflammation. Knowledge Gap: Soy isoflavones, while potentially providing renal protection, their impact on renal and hematologic parameters in glycerol-induced AKI models has not been thoroughly studied. Aims: The study evaluated the effectiveness of soy isoflavones in regulating renal and hematologic parameters in a glycerol-induced AKI rat model, assessing their potential as therapeutic agents. Results: The study involving adult female Wistar rats showed that pretreatment with glycerol or dihydroxystilbene significantly reduced urinary β2-microglobulin, albumin, BUN, and serum creatinine levels in the AKI-induced group, reversing hematological changes. Novelty: The study explores the protective effects of soy isoflavones on renal function and hematologic parameters in AKI, highlighting GN's superior efficacy over DZ. Implications: Soy isoflavones, particularly GN, may be potential preventive or therapeutic strategies for AKI caused by rhabdomyolysis, warranting further research for clinical applications. Highlights: GN and DZ reduce kidney damage in glycerol-induced AKI. GN is more effective than DZ in kidney and blood parameters. Soy isoflavones could treat or prevent AKI. Keywords: Acute kidney injury, soy isoflavones, glycerol-induced AKI, renal protection, hematologic parameters

Prevention of glycerol-induced acute kidney injury by isoflurane inhalation in male rats

Prevention of glycerol-induced acute kidney injury by isoflurane inhalation in male rats

Therapeutic potential of urine-derived stem cells in renal regeneration following acute kidney injury: A comparative analysis with mesenchymal stem cells.

Acute kidney injury (AKI) is a common clinical syndrome with high morbidity and mortality rates. The use of pluripotent stem cells holds great promise for the treatment of AKI. Urine-derived stem cells (USCs) are a novel and versatile cell source in cell-based therapy and regenerative medicine that provide advantages of a noninvasive, simple, and low-cost approach and are induced with high multidifferentiation potential. Whether these cells could serve as a potential stem cell source for the treatment of AKI has not been determined. To investigate whether USCs can serve as a potential stem cell source to improve renal function and histological structure after experimental AKI. Stem cell markers with multidifferentiation potential were isolated from human amniotic fluid. AKI severe combined immune deficiency (SCID) mice models were induced by means of an intramuscular injection with glycerol. USCs isolated from human-voided urine were administered via tail veins. The functional changes in the kidney were assessed by the levels of blood urea nitrogen and serum creatinine. The histologic changes were evaluated by hematoxylin and eosin staining and transferase dUTP nick-end labeling staining. Meanwhile, we compared the regenerative potential of USCs with bone marrow-derived mesenchymal stem cells (MSCs). Treatment with USCs significantly alleviated histological destruction and functional decline. The renal function was rapidly restored after intravenous injection of 5 × 105 human USCs into SCID mice with glycerol-induced AKI compared with injection of saline. Results from secretion assays conducted in vitro demonstrated that both stem cell varieties released a wide array of cytokines and growth factors. This suggests that a mixture of various mediators closely interacts with their biochemical functions. Two types of stem cells showed enhanced tubular cell proliferation and decreased tubular cell apoptosis, although USC treatment was not more effective than MSC treatment. We found that USC therapy significantly improved renal function and histological damage, inhibited inflammation and apoptosis processes in the kidney, and promoted tubular epithelial proliferation. Our study demonstrated the potential of USCs for the treatment of AKI, representing a new clinical therapeutic strategy.

Kidney-targeted antioxidant salvianolic acid B nanoparticles restoring lysosome homeostasis for acute kidney injury therapy

Acute kidney injury (AKI) is highly correlated with oxidative stress, and the application of antioxidants is one of the promising treatments. Salvianolic acid B (SAB) is a natural polyphenol with powerful antioxidant effects. Due to its inherent characteristic of inferior bioavailability, its clinical application is impeded. In this study, small SAB-incorporated nanoparticles (SFA) were synthesized via the self-assembly of SAB, ferric ions, and bovine serum albumin (BSA). Apart from antioxidant activity, the SFA nanoparticles were found to efficiently restore lysosome dysfunction induced by reactive oxygen species (ROS) in human kidney proximal tubular epithelial HK-2 cells. The small size and BSA incorporation make the SFA nanoparticles to be promising AKI-targeting nanoparticles. They are rapidly accumulated and long-term retained in injured kidneys of glycerol-induced AKI mice, especially in the proximal tubules which are the key lesion location during AKI. In vivo studies indicate that SFA nanoparticles show a superior protective effect compared with the free drug by suppressing oxidative stress and maintaining lysosome homeostasis indicated by enhanced heme oxygenase-1 (HO-1) expression and restored cathepsin B (CTSB) activity, respectively. In summary, this study develops a delivery system for the antioxidant SAB enhancing local delivery and offering an additional lysosome restoring mechanism for AKI therapy.

Renal protection by ellagic acid in a rat model of glycerol-induced acute kidney injury.

Studies conducted on animal models have shown that the administration of glycerol can lead to kidney tissue damage and impaired renal function. This is believed to be caused by oxidative stress and inflammation, which in turn can result in elevated levels of blood urea nitrogen (BUN) and creatinine. These metabolites are commonly used as indicators of renal function. The aim of the current experimental research was to investigate the protective efficacy of ellagic acid in a rat model of rhabdomyolysis induced by glycerol. Sixty healthy adult male Wistar rats weighing between 250 - 300 g were divided into five equal groups including control, rhabdomyolysis (administered 8.00 mL kg-1 of glycerol), and three rhabdomyolysis plus various doses of ellagic acid (25.00, 50.00 and 100 mg kg-1 per day; 72 hr after receiving glycerol for 14 days successively) groups. Serum levels of BUN, creatinine, lactate dehydrogenase, alkaline phosphatase, electrolytes and inflammatory cytokines were evaluated in all rats. Histopathological studies were also performed on kidney tissues from all groups. The administration of ellagic acid resulted in a significant increase in renal function biomarkers compared to the rats with acute kidney injury. This increase was consistent with notable reductions in tumor necrosis factor-α levels and increases in interleukin-10 levels observed in blood samples. Furthermore, the improvement in histopathological indices observed in rats received ellagic acid confirmed its nephroprotective role. The results of the current experimental study suggest that ellagic acid can improve kidney damage following glycerol injection, potentially by modulating the inflammatory process.

Modulation of inflammatory, oxidative, and apoptotic stresses mediates the renoprotective effect of daidzein against glycerol-induced acute kidney injury in rats.

Acute kidney injury (AKI) is a life-threatening complication that accompanies rhabdomyolysis. Daidzein is a dietary isoflavone that has various biological activities. This study examined the therapeutic potential of daidzein and the underlying mechanisms against AKI induced by glycerol in male rats. Animals were injected once with glycerol (50%, 10 ml/kg, intramuscular) for induction of AKI and pre-treated orally with daidzein (25, 50, and 100 mg/kg) for 2 weeks. Biochemical, histopathological, immunohistopathological, and molecular parameters were assessed to evaluate the effect of daidzein. The results revealed that the model group displayed remarkable functional, molecular, and structural changes in the kidney. However, pre-administration of daidzein markedly decreased the kidney relative weight as well as the levels of urea, creatinine, K, P, kidney injury molecule-1 (KIM-1), neutrophil gelatinase-associated lipocalin (NGAL), and cystatin C. Further, daidzein lessened the rhabdomyolysis-related markers [lactate dehydrogenase (LDH) and creatine kinase (CK)]. Notably, the enhancement of the antioxidant biomarkers [superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), and reduced glutathione (GSH) is accompanied by a decrease in malondialdehyde (MDA) and nitric oxide (NO) levels. Moreover, upregulated gene expression levels of nuclear factor erythroid 2-related factor 2 (Nfe212) and hemeoxygenase-1 (Hmox1) were exerted by daidzein administration. Rats who received daidzein displayed markedly lower interleukin-1β (IL-1β), tumor nuclear factor-α (TNF-α), myleoperoxidase (MPO), and nuclear factor kappa B (NF-κB) levels together with higher interleukin-10 (IL-10) related to the model group. Remarkably, significant declines were noticed in the pro-apoptotic (Bax and caspase-3) and rises in antiapoptotic (Bcl-2) levels in the group that received daidzein. The renal histological screening validated the aforementioned biochemical and molecular alterations. Our findings support daidzein as a potential therapeutic approach against AKI-induced renal injury via suppression of muscle degradation, oxidative damage, cytokine release, and apoptosis.

Protective Effects of Citronellol Against Rhabdomyolysis-Induced Acute Kidney Injury in Mice by Inhibiting NF-κB and IL-1β

Objectives: acute kidney injury (AKI) is a serious pathophysiology side effect of rhabdomyolysis. Inflammatory mechanisms play a role in the development of rhabdomyolysis-induced AKI. Citronellol (CT) is a naturally occurring monoterpene alcohol (3,7-Dimethyl-6-often-1-ol) found in aromatic plant species' essential oils. In this study, we explored the protective effects of Citronellol on glycerol-induced AKI.
 Methods: Four groups of eight mice each (n=8) were formed by randomly dividing the animals into the groups, glycerol-induced AKI model group, low-dose CT-treated group (50mg/kg), high-dose CT-treated group (100mg/kg), and control group. The renal functions of mice from all groups were evaluated using serum urea and creatinine. Creatine kinase (CK) level was used to detect rhabdomyolysis. Inflammatory response was determined using Nf-kB and iL-1B levels.
 Results: Citronellol in both doses 50&100 mg/kg significantly decreased serum urea, creatinine and CK as Compared to the glycerol group, as well as treatment with citronellol resulted in a lower expression of both NF-κB and IL-1β in the renal tissue, indicating that citronellol may have an anti-inflammatory effect in AKI.
 Conclusion: prophylaxis with low and high doses of citronellol improved inflammatory responses and renal function. It's possible that by inhibiting Nf-kB and iL-1B, these positive effects were achieved, inhibiting the development of inflammatory cytokines as a result. These discoveries reveal fresh details regarding a potential treatment option for kidney injury caused by rhabdomyolysis.

Nephroprotective Efficacy of Echinops spinosus against a Glycerol-Induced Acute Kidney Injury Model.

Nephroprotection or renal rescue is to revive and restore kidney function after damage, with no need for further dialysis. During acute kidney injury (AKI), sudden and recent reductions in kidney functions occur. Causes are multiple, and prompt intervention can be critical to diminish or prevent morbidity. Echinops spinosus (ES) is a curative plant with proven pharmacological and biological effects including anti-inflammatory, antioxidant, and antibacterial competencies. The principal goal of this research is to scrutinize the nephroprotective features of E. spinosa extract (ESE) against glycerol-induced AKI. Male Wistar albino rats were equally divided into five separated groups: negative control rats (vehicle-injected), ESE control rats (ESE-treated rats), positive control rats, glycerol-induced AKI-model rats (single IM injection of 50% glycerol), and 2 groups of diseased rats but pretreated with different concentrations of ESE for 7 days (ESE150 + AKI rats and ESE250 + AKI rats). Kidney tissues were collected and used for histopathology analysis. The relative kidney weight percentage was assessed. ESE effects were investigated via scanning several biomarkers, such as serum urea and creatinine, as kidney function biomarkers. Lactate dehydrogenase (LDH) and creatine kinase (CK) activities were examined as rhabdomyolysis (RM) indicators. Kidney injury molecule-1 (Kim-1) and neutrophil gelatinase-associated lipocalin (NGAL) were also examined to investigate kidney injury. Enzymatic and nonenzymatic oxidative stress markers were analyzed, namely, superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), glutathione peroxidase (GPx), malondialdehyde (MDA), nitric oxide (NO), and reduced glutathione GSH. Proinflammatory cytokine [tumor necrosis factor-α (TNF-α) and interleukin-1 β (IL-1β)] and the renal proapoptotic protein (Bax) and antiapoptotic protein (Bcl-2) levels were evaluated. Statistical analysis for the resulting data revealed that ESE pretreatment turned AKI-induced biological antioxidant levels to an extent comparable to normal results. Furthermore, ESE decreased kidney function markers and RM-related biomarkers (LDH, CK, Kim-1, and NGAL) compared to those in untreated AKI-model rats. ESE treatment dropped the apoptotic renal Bax levels, enhanced antiapoptotic Bcl-2 manufacture, and disallowed the release of IL-1β and TNF-α. This study revealed the protective effect of ESE as therapeutic medicine against AKI-encouraged oxidative stress, inflammation, and apoptosis. It can be effectively used as adjuvant therapy, helping in renal rescue, and for kidney healing in cases with risk factors of AKI.

N-Acetylcysteine Improves Renal Function and Reduces Tissue Malondialdehyde Levels in Glycerol-Induced Acute Kidney Injury

Introduction: The etiology of myoglobinuric acute kidney injury involves oxidative injury brought on by the Fenton reaction and myoglobin redox cycle. Renal tubules may be harmed, and lipid peroxidation compounds with vasoconstrictor characteristics may be produced. N-acetylcysteine (NAC) is an antioxidant shown to improve renal microcirculation and have protective effects in various models of renal damage. The aim of the study was to demonstrate the protective impact of NAC in glycerol-induced rats by measuring tissue malondialdehyde (MDA) level and renal function test (RFT), and to determine the correlation between the protective effect and NAC dose.Methods: This study measured tissue malondialdehyde (MDA) and renal function to examine any protective effect of NAC in a glycerol-induced rat model and to determine whether the effect was dose-related. Five groups of male Wistar rats were used: 1) saline control group, (2) glycerol (50%, 8mL/kg, i.m) plus saline i.v group, 3) glycerol plus NAC (100 mg/kg)-treated group, 4) glycerol plus NAC (200 mg/kg)-treated group, 5) glycerol plus NAC (400 mg/kg)-treated group. At 24 hrs, after glycerol injection, rats were sacrificed, cardiac blood was taken for renal function measurement, and renal tissues were removed for thiobarbituric acid MDA level assessment.Results: Our study revealed that glycerol administration significantly amplified renal tissue MDA, serum creatinine, and BUN (blood urea nitrogen) levels. However, NAC administration dampened the MDA increment and renal function deterioration (p<0.05). Moreover, tissue MDA, BUN, and serum creatinine levels were significantly correlated to NAC dose (r=0.485; r=0.491; rs=0.544, respectively; all p<0.05), indicating that NAC protection declines by dose increments.Conclusion: In this glycerol-induced acute kidney injury rat model, the administration of intravenous NAC 100 mg/kg reduced lipid peroxidation and improved renal function. Nevertheless, the protective effect was diminished in higher doses.

Protective effect of thymol on glycerol-induced acute kidney injury

Acute kidney injury (AKI) is a syndrome characterized by an accelerating decrease in renal function in a short time. Thymol is one of the main components of thyme species and has a variety of pharmacological effects. Here, we investigated whether thymol could ameliorate rhabdomyolysis (RM)-induced AKI and its related mechanism. Glycerol was used to induce RM-associated AKI in rats. Rats received thymol (20 mg/kg/day or 40 mg/kg/day) gavage 24 h before glycerol injection until 72 h after injection daily. Kidney injury was identified by measuring serum creatinine (Scr) and urea levels and by H&E and PAS staining and immunohistochemistry (the expression of proliferating cell nuclear antigen (PCNA)). Renal superoxide dismutase (SOD), malondialdehyde (MDA), and oxidative stress-related Nrf2/HO-1 signaling pathways were measured. The expression of the inflammatory markers TNF-α, IL-6, MCP-1, and NF-κB was assessed by ELISA and western blotting. Finally, the expression of the PI3K/Akt signaling pathway was detected by western blotting. Glycerol administration induced obvious renal histologic damage and increased Scr, urea, and PCNA expression. Notably, thymol treatment attenuated these structural and functional changes and prevented renal oxidative stress, inflammatory damage and PI3K/Akt pathway downregulation associated with glycerol-induced AKI. In conclusion, thymol might have potential applications in the amelioration of AKI via its antioxidant and anti-inflammatory effects and upregulation of the PI3K/Akt signaling pathway.

Disruption of CD40 Results in Significantly Attenuated Renal Inflammation Following Glycerol-Induced Acute Kidney Injury

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Alpha-Mangostin ameliorates acute kidney injury via modifying levels of circulating TNF-α and IL-6 in glycerol-induced rhabdomyolysis animal model.

Alpha mangostin (AM), isolated from G. mangostana, showed beneficial effects in several disorders due to its antioxidant and anti-inflammatory properties. Acute kidney injury (AKI) due to different etiologies can develop into severe complications, resulting in high mortality rates. In this work, AM is tested for its ability to alleviate AKI in glycerol-induced AKI rat model, where 30 Male Sprague-Dawley rats were assigned to a healthy group, glycerol-treated group and AM-treated group. Glycerol- and AM groups received a single dose of glycerol (per IM, 50% glycerol in saline, 8 ml/kg), whereas control group was injected with saline. AM treatment (a single daily dose, per IP, 175mg/kg) was accomplished for three days. Animals were executed to collect blood samples and kidney tissue for biochemical and histological examination. It was found that glycerol induced increase in serum creatinine, blood urea nitrogen (BUN), lipid peroxidation, serum magnesium, TNF-α and IL-6. It also induced renal edema and hypocalcemia along with histopathological renal damage. AM treatment improved renal histological features and alleviated increase in serum creatinine, BUN, serum magnesium, TNF-α and IL-6 levels, as well as renal edema and lipid peroxidation but did not affect serum calcium levels. This suggests AM as a potential therapeutic agent for treating AKI mainly via its antioxidant and anti-inflammatory properties.

Therapeutic propensity of ginsenosides Rg1 and Rg3 in rhabdomyolysis-induced acute kidney injury and renohepatic crosstalk in rats.

Ginseng is a traditional herbal medicine used for thousands of years in Southeast Asian countries because of its medicinal properties. Ginsenosides Rg1 and Rg3 have demonstrated therapeutic properties against a broad spectrum of diseases. Here in this study, we investigated the therapeutic efficacy of Rg1 and Rg3 in alleviating glycerol-induced acute kidney injury, also known as rhabdomyolysis-induced acute kidney injury (RAKI). AKI was induced in male Wistar rats through intramuscular injection of 10 mL/kg glycerol and simultaneous oral treatment of ginsenosides Rg1 and Rg3 for 3 days. We also evaluated the therapeutic potential of Rg1 and Rg3 on human embryonic kidney epithelial (HEK-293). Cell viability and LDH assay were performed on HEK-293 cells to evaluate the toxicity of Rg1 and Rg3. Evaluation of important kidney damage markers such as creatinine and blood urea nitrogen (BUN) was carried out at different time points from the rat serum. Histopathological analysis was performed on kidney tissues. We also performed experiments such as ELISA assay, immunohistochemistry, immunofluorescence staining, COMET assay, western blotting, TUNEL assay, and flow cytometry to obtain results. Rg1 and Rg3 significantly downregulated the expression of kidney damage markers such as creatinine and BUN in a dose-dependent manner. Histopathological analysis revealed damage across the glomerulus, tubules, and collecting duct rendering the kidney dysfunctional in glycerol treatment groups. However, Rg1 and Rg3 treated groups showed a significant reduction in tubular necrosis at both 10 and 20 mg/kg. There was also a sharp downregulation of oxidative and ER stress markers. Additionally, we observed nuclear translocation of Nrf2 which were more prominent in kidney tissues. Rg1 and Rg3 were also able to mitigate apoptotic cell death in vitro and in vivo evaluated through immunofluorescence staining for p53, TUNEL assay, flow cytometry, and immunoblotting for intrinsic apoptosis markers. In summary, we conclude that Rg1 and Rg3 exhibited natural therapeutic remedy against AKI.

Renoprotective effect of vinpocetine and cilostazol on glycerol induced renal injury in male rats

Acute kidney injury (AKI) is characterized by a sudden loss of kidney function that is established by increased serum creatinine levels and decreased urinary output. AKI is one of a group of functional kidney conditions
 known as acute kidney disease and disorders (AKD), which can vary in severity and self-limiting to severe and chronic. Adminstrations of glycerol generate significant elevation in serum urea and creatinine that’s mean occurance of functional abnormalities in the kidney. Vinpocetine drug has many pharmacological targets with multiple action, phosphodiesterase inhibiters-1(PDE-1) inhibitor, a voltage-gated sodium channel, and Inhibitory kinase B (IKK) are 3 main molecule targets of vinpocetine. PDE1 has been implicated in the regulation of vasoconstriction, vascular and cardiac structure remodeling, and neuro-transmission. Cilostazol, a phosphodiesterase (PDE) III inhibitors, that widely used for many cases such as reduces direct vascular injury via different mechanism, such as vasodilation and antiplatelet action, anti-inflammation and platelet-leukocyte interaction minimisation, and inhibition of vascular proliferation via up-regulation of hepatocyte growth factors. In present study, we looked at the effect and mechanism of the drugs vinpocetine and cilostazol in an animal model of glycerol-induced AKI. Experiment done during the 14-day trial, rats were divided into five groups: the control group received 2ml/kg normal saline; the induction group received 10ml/kg intramuscular glycerol injection; the vinpocetine group received 5mg/kg via gavage for 14 days and on day 7 given glycerol IM, the cilostazol group received 50mg/kg for 14 days and on day 7 given glycerol IM, and the combination group received half dose vinpocetine (2.5mg/kg) and cilostazol (25mg/kg). We discovered that the induction group had higher levels of urea and creatinine, as well as increased inflammation and oxidative stress, and that their renal tissue showed morphological changes typical of AKI, whereas the combination groups reduced glycerol induce acute renal damage. This revealed that vinpocetine and cilostazol can reinforce renal rat protection by reducing serum urea and creatinine and improving histopathological changes.

Visnagin Mitigates Glycerol-induced Acute Kidney Injury in Rats through Decreasing Inflammation, Oxidative Stress, and Renal Dysfunction Markers

Abstract: Background: Acute kidney injury (AKI) is a heterogenous condition, characterized by dysregulated kidney function along with reduced glomerular filtration, solute excretion, and urine output. Objectives: This work was focused to investigate the therapeutic roles of visnagin against the glycerol-induced AKI in rats via reducing the inflammation and oxidative stress responses. Materials and Methods: The AKI was induced in the Wistar rats by injecting 50% of glycerol (10 ml/kg). Then AKI rats were treated with 20 and 40 mg/kg of visnagin, respectively for 12 consecutive days. The rats were sacrificed followed at the end of experiments and blood and renal tissue samples were collected. The creatinine, BUN, urea, and LDH was quantified using assay kits. The nitric oxide (NO), MDA, and MPO were analyzed using assay kits. The antioxidants such as GSH, SOD, GSH, GPx, GR, and CAT activities were assessed by the standard methods. The IL-1β, IL-6, TNF-α, TGF-β1, MCP-1, and ICAM-1 levels were measured using assay kits. The histopathological analysis was done on the renal tissues. Results: The 20 and 40 mg/ kg of visnagin treatment reduced the relative kidney weight of AKI rats. The urea, creatinine, BUN, and LDH levels were diminished by the visnagin. The 20 and 40 mg/kg of visnagin treated AKI rats appreciably reduced the MDA, MPO, and NO levels and augmented the GSH, SOD, GPx, GR, and CAT activities in the renal tissues. The IL-6, IL-1β, TNF-α, and TGF-1β levels were reduced by the visnagin treatment. The MCP-1 and ICAM-1 status were also diminished by the visnagin. The findings of the histopathological analysis revealed that visnagin attenuated the glycerolinduced AKI in rats. Conclusion: In conclusion, the outcomes of this study revealed that the visnagin demonstrated nephroprotective effects against glycerol-induced renal damage in rats. The ability of visnagin to ameliorate inflammatory response, oxidative stress, and renal dysfunction make it a potential candidate for treating AKI. Keywords: Glycerol, Renal dysfunction, Creatinine, Inflammation, Visnagin, Rhabdomyolysis.

Ovariectomy exacerbates glycerol-induced acute kidney injury in rats

Objective: This study aimed to evaluate the effects of ovariectomy on glycerol-induced renal changes in rats. Methods: Twenty-four female Wistar rats were submitted to ovariectomized (OVX) or sham surgery. One week after surgery, the animals received an intramuscular injection (8ml/kg) of 50% glycerol or saline (0.15 M) solution. These animals were divided into the following groups (n=6 per group): Sham, sham-operated female rats injected with saline; OVX, ovariectomized female rats injected with saline; Sham+Gly, sham-operated female rats injected with glycerol; OVX+Gly, ovariectomized female rats injected with glycerol. All rats were euthanized 3 days after the injections and the kidneys were removed for histological and immunohistochemical studies. Blood and urine samples were also collected for renal function studies. Results: The OVX+Gly group presented higher creatinine serum levels, as well as greater fractional excretion of sodium and urinary flow than the Sham+Gly group. Histological lesions and tubulointerstitial staining for macrophages, nuclear factor-kappa B, and nitrotyrosine were more pronounced in the renal cortex of the OVX+Gly group compared to the Sham+Gly group. Conclusion: We conclude that ovariectomy aggravated changes in renal function and structure in glycerol-induced acute kidney injury by the intensification of the proinflammatory tissue response.

Hydrogenated Germanene Nanosheets as an Antioxidative Defense Agent for Acute Kidney Injury Treatment.

Acute kidney injury (AKI) is a sudden kidney dysfunction caused by aberrant reactive oxygen species (ROS) metabolism that results in high clinical mortality. The rapid development of ROS scavengers provides new opportunities for AKI treatment. Herein, the use of hydrogen-terminated germanene (H-germanene) nanosheets is reported as an antioxidative defense nanoplatform against AKI in mice. The simulation results show that 2D H-germanene can effectively scavenge ROS through free radical adsorption and subsequent redox reactions. In particular, the H-germanene exhibits high accumulation in injured kidneys, thereby offering a favorable opportunity for treating renal diseases. In the glycerol-induced murine AKI model, H-germanene delivers robust antioxidative protection against ROS attack to maintain normal kidney function indicators without negative influence in vivo. This positive in vivo antioxidative defense in living animals demonstrates that the present H-germanene nanoplatform is a powerful antioxidant against AKI and various anti-inflammatory diseases.

Inhalation of 4% and 67% hydrogen ameliorates oxidative stress, inflammation, apoptosis, and necroptosis in a rat model of glycerol-induced acute kidney injury

Acute kidney injury (AKI) is the major complication of rhabdomyolysis (RM) clinically, which is usually mimicked by glycerol injection in basic research. Oxidative stress, inflammatory response and apoptosis are recognized to play important roles in development of this disease. Recently, numerous studies have reported the therapeutic effects of molecular hydrogen (H2) on oxidative stress and inflammation-related diseases. Here, the effects of H2 against glycerol-induced AKI and the underlying mechanisms were explored in rats. Low (4%) and high (67%) concentrations of H2 were prepared using a self-made device to investigate the dose-response. After 72 hours of glycerol injection (8 mL/kg), we found that glycerol triggered oxidative stress, inflammatory reactions, and apoptotic events. These caused subsequent renal damage, evidenced by a significant reduction of antioxidases and up-regulation of the relevant damaged biomarkers. H2 inhalation reversed the above alterations and exerted renoprotective effects. Interestingly, for RM/AKI-related factors, no consistent dose-response benefits of H2 were observed. However, higher concentration of H2 inhalation improved histological and morphological changes better. This study suggests that H2 is a potential alternative therapy to prevent or minimize RM induced AKI possibly via its antioxidant, anti-inflammatory, anti-apoptotic and anti-necroptotic properties.

Pilot testing for long-term impact of glycerol-induced acute kidney injury on oxalate homeostasis in rats

Abstract. There is a general lack of research on the long-term effects of acute kidney injury (AKI) on oxalate-degrading bacteria (ODB) and their total oxalate-degrading activity (ODA) in fecal microbiota. In the present pilot study, we separately evaluated the changes in the ODB number and their total ODA in fecal microbiota at 3-time points after glycerol-induced AKI. In addition, we assessed the interactions between AKI-induced renal histopathological changes and ODB, total fecal ODA, and plasma and urine oxalate concentrations in rats.
 Methods. The male Wistar rats (200-300 g, n = 20) on oxalate-free diet were randomly divided into 2 groups. After 24-h of water deprivation, experimental group 1 (n = 10) received an intramuscular injection of 50% glycerol (10 ml/kg of body weight), and group 2 (n = 10) served as a control. The numbers of ODB (incubated in a highly selective Oxalate Medium and determined using the culture method), total fecal ODA and urinary oxalate (UOx) excretion were measured after injection on days 8, 22 and 70. The method of redoximetric titration with a KMnO4 solution was adopted to evaluate total ODA in fecal microbiota. Renal injury was assessed by histopathology examination, serum creatinine plasma oxalic acid (POx) concentration and daily proteinuria levels after removing the animals from the experiment on day 70.
 Results. After glycerol injection on days 8 and 22, no differences were found in the numbers of ODB, their total fecal ODA, and UOx excretion level between the experimental and control groups. However, after AKI initiation on day 70, the numbers of ODB, total fecal ODA, and daily UOx excretion were significantly lower in the experimental group as compared with the control group. In addition, in 10 weeks following AKI, the number of ODB had a direct correlation with UOx excretion and an inverse correlation with POx and serum creatinine concentrations and daily proteinuria. Total ODA in fecal microbiota was directly associated with the percentage of renal interstitial fibrosis and the average glomerular volumes in the experimental rats.
 Conclusions: AKI had long-term negative effects on the quantitative and qualitative characteristics of ODB in fecal microbiota in rats. Moreover, the results of our study confirmed an increasing trend in total fecal ODA according to the aggravation of renal interstitial fibrosis and glomerular volume in rats’ kidneys. Further studies are warranted to gain more insight into the mechanism of oxalate homeostasis impairment in AKI.

Annona muricata mitigates glycerol-induced nephrotoxicities in male albino rats through signaling pathways of angiotensin conversion enzyme, kidney injury molecule-1, and antioxidant properties

ObjectiveThe ameliorative effect of Annona muricata in glycerol-induced acute kidney injury in laboratory rats was evaluated. MethodsThirty albino rats were used and were divided into five of six rats per group. The first (control) group was given distilled water (2 ml/kg) for seven days, while the second (toxicant or glycerol alone) group was given only glycerol (10 ml/kg) on day 8. The third, fourth, and fifth groups received methanol leaf extract of Annona muricata (100 mg/kg), 200 mg/kg dose of the extract, and enalapril (10 mg/kg) respectively for seven days, and on day eight all received glycerol (10 ml/kg). Serum chemistry, histopathology, immunohistochemistry, and changes in blood pressure were indices of toxicity. ResultsIn the toxicant group, blood pressure increased significantly (p<0.05), but treatment with 200 mg/kg of the leaf extract reversed this. In biochemical analysis, the toxicant group had a significant increase in the levels of oxidative stress markers and decreased levels of some enzymatic and non-enzymatic antioxidants. Treatment with 200 mg/kg of the extract and enalapril reversed the trend. Histopathological changes were seen in the kidney of the toxicant group, but those treated with 200 mg/kg of the extract showed normal kidney histology with no observable lesion. The immunolocalization of angiotensin-converting enzyme and kidney injury molecule-1 in the kidney showed high expression of these proteins in the toxicant group. At the same time, enalapril and the extract caused significant downregulation of their expressions. ConclusionResults showed that 200 mg/kg dose extract of Annona muricata could confer effective protection on the kidney due to its anti-inflammatory, anti-hypertensive and antioxidant properties.