Alterations in Oxidative Stress Markers and Na,K-ATPase Enzyme Properties in Kidney after Fructose Intake and Quercetin Intervention in Rats

The Protective Effect of Boric Acid Against High Fructose-Induced Liver and Kidney Damage in Rats

This study aimed to determine the protective role of boric acid (BA) in high fructose (HF)-induced liver and kidney toxicity in a young rat model. High-fructose consumption causes serious damage to liver and kidney tissue in healthy individuals and contributes to the emergence of various metabolic diseases. Thirty-two healthy female Wistar albino rats (250-300 g weight and 3-4 months) were randomly distributed into four equal groups (n = 8): control, high fructose % 20 (HF), boric acid 20 mg/kg (BA), and HF + BA. High fructose was freshly prepared and administered to the rats as 20 g of D-fructose dissolved in 100 mL of tap water daily for a duration of 30 days. Boric acid (20 mg/kg) was administered through gastric gavage throughout the 30-day study period. At the end of study, blood, liver, and kidney were collected from rats. The results indicated that high fructose induced increased glucose, total cholesterol, triglyceride, and urea levels in rat serum. Boric acid administration significantly decreased glucose, total cholesterol, triglyceride, and urea levels in HF + BA groups. The results indicated that high fructose-induced oxidative stress by increasing the level of MDA and by decreasing GSH levels, and CAT activity in the liver and kidney of rats. However, oral BA administration significantly decreased MDA levels and increased GSH levels, and CAT activity (p < 0.05). Furthermore, BA significantly reduced high fructose-induced histopathological and Immunohistochemistry alteration in the liver and kidney tissues. In conclusion, BA may prevent the oxidative imbalance and histopathological and immunohistochemical damage caused by high fructose in liver and kidney tissues in rats.

The potential of fruit ethanolic extract Etlingera hemisphaerica as a solution for hyperglycemia, uremia, and hypercreatininemia in mice (Mus musculus)

Background

Leaf ethanolic extract of Etlingera hemisphaerica (LE3H) has the potential to restore glucose, triglyceride, and uric acid disorders and reduce mercury toxicity. High levels of glucose (hyperglycemia), urine (uremia), and creatinine (hypercreatininemia) in the blood cause real health problems. Meanwhile, the phytochemical content in fruit ethanolic extract of E. hemisphaerica (FE3H) is higher than that of LE3H.

Aim

This study evaluated the potential of FE3H as a solution for hyperglycemia, uremia, and hypercreatininemia in mice.

Methods

Quercetin levels in FE3H were determined by high-performance liquid chromatography. The first (A) stage used 25 male mice divided into five groups. On day (d)1, the body weight (BW) of the mice was weighed. On d2-11, 5-mg/gBW sucrose was given by gavage, and then, on d12, BW and blood glucose level of mice were determined. On d13, 0.52-mg/gBW glibenclamide was given in A2, 0.39-mg/gBW FE3H was given in A3, and 0.52-mg/g BW FE3H was given in A4 by gavage. Control, A0, was only given double-distilled water (DDW). On d14, BW and blood glucose levels of the mice were determined. The second (B) stage used 24 male mice divided into six groups. On d1, B1-B5 were injected intraperitoneally 5-mg/kg BW HgCl2; then, on d3-5, they were given by gavage 0.2-mg/g BW Immunos® in B2, 0.39-mg/gBW FE3H in B3, 0.52-mg/gBW FE3H in B4, and 0.65-mg/gBW FE3H in B5. Controls, B0 and B1, were only given DDW. On d6, the mice were killed by cervical dislocation. The weight of the kidney was determined, and then, the urea and creatinine levels were measured in blood samples from the heart.

Results

FE3H contains 98.92 ± 12.88 µg/g quercetin. Sucrose tends to increase BW, and then, 0.39-mg/g BW FE3H treatment tends to restore BW close to control. Sucrose significantly increased blood glucose, and then, 0.39- and 0.52-mg/gBW FE3H treatment restored significantly blood glucose similar to control. HgCl2 increases kidney weight, and then, 0.65-mg/gBW FE3H treatment tends to restore kidney weight close to control. HgCl2 significantly increased urea and creatinine, and then, 0.52- and 0.65-mg/gBW FE3H treatment significantly restored urea and creatinine similar to the control.

Conclusion

FE3H, which is high in flavonoid quercetin, has the potential to restore hyperglycemia by 47.38%-48.18%, uremia by 29.04%-33.06%, and hypercreatininemia by 49.52%-54.28% in mice.

Deleterious Effect of Fructose on the Heart Function of Hypertriglyceridemic Rats

A high-fructose intake (HFI) in food, sweetened beverages, and soft drinks appears to be one of the risk factors that worsens human metabolic and cardiovascular health, although the more accurate mechanism remains unclear. Hypertriglyceridemic (HTG) rats represent a suitable animal model of metabolic syndrome where the consumption of an HFI could have an additional aggravating impact. We aimed to study the effect of fructose on the heart functions. Male HTG rats had HFI or a standard diet for five weeks. Heart function was tested ex vivo on the perfused heart using the Langendorff technique. Isolated hearts underwent 25 min ischemia (I) and 30 min reperfusion (R). Left ventricular developed pressure (LVDP), ventricular premature beats, and dysrhythmias were monitored during R. At the end of the R, ventricular fibrillation (VF) was evoked electrically. Systolic blood pressure, glucose level, serum total cholesterol (TC), triglycerides (TAG), and thiobarbituric acid reactive substances (TBARS) in the kidney were determined. The LVDP showed a reduced return to the input values, the duration of VF in R increased, and the threshold for VF induction decreased. Serum TC, TAG, and kidney TBARS were increased. The effect of HFI on heart ventricular impairment was associated with the reduced threshold for induction of VF and aggravated dyslipidemia. The results point to the adverse impact of dietary high-fructose intake in rats with hypertriglyceridemia.

Oxidative Stress Induced by Lipotoxicity and Renal Hypoxia in Diabetic Kidney Disease and Possible Therapeutic Interventions: Targeting the Lipid Metabolism and Hypoxia

Oxidative stress, a hallmark pathophysiological feature in diabetic kidney disease (DKD), arises from the intricate interplay between pro-oxidants and anti-oxidants. While hyperglycemia has been well established as a key contributor, lipotoxicity emerges as a significant instigator of oxidative stress. Lipotoxicity encompasses the accumulation of lipid intermediates, culminating in cellular dysfunction and cell death. However, the mechanisms underlying lipotoxic kidney injury in DKD still require further investigation. The key role of cell metabolism in the maintenance of cell viability and integrity in the kidney is of paramount importance to maintain proper renal function. Recently, dysfunction in energy metabolism, resulting from an imbalance in oxygen levels in the diabetic condition, may be the primary pathophysiologic pathway driving DKD. Therefore, we aim to shed light on the pivotal role of oxidative stress related to lipotoxicity and renal hypoxia in the initiation and progression of DKD. Multifaceted mechanisms underlying lipotoxicity, including oxidative stress with mitochondrial dysfunction, endoplasmic reticulum stress activated by the unfolded protein response pathway, pro-inflammation, and impaired autophagy, are delineated here. Also, we explore potential therapeutic interventions for DKD, targeting lipotoxicity- and hypoxia-induced oxidative stress. These interventions focus on ameliorating the molecular pathways of lipid accumulation within the kidney and enhancing renal metabolism in the face of lipid overload or ameliorating subsequent oxidative stress. This review highlights the significance of lipotoxicity, renal hypoxia-induced oxidative stress, and its potential for therapeutic intervention in DKD.

Quercetin-targeted AKT1 regulates the Raf/MEK/ERK signaling pathway to protect against doxorubicin-induced nephropathy in mice

BACKGROUND

Doxorubicin is an anthracycline antitumor agent commonly used in clinical practice, which has some nephrotoxicity and is often used to establish mouse models of kidney injury for basic medical research. This study will investigate the protective effect of quercetin on renal function in doxorubicin-induced nephropathy mice.

METHODS

C57BL/6 mice were divided into control, model, and quercetin low-, and high-dose groups. Serum and urine were collected to analyze markers of kidney function. H&E staining was used to detect pathological changes in renal tissues. Transmission electron microscopy was performed to observe the ultrastructural changes in renal tissues. Immunohistochemistry was performed to detect the changes of Ang II. RT-qPCR was performed to detect the changes of cytokines. ELISA was used to detect changes in serum inflammatory factors. Molecular docking was performed to verify the targeting relationship between quercetin and AKT1. Western blot was performed to detect Bax, Bcl-2, Cyt-c, AKT1, Raf, MEK, and ERK proteins.

RESULTS

Quercetin could induce the recovery of kidney function in kidney-injured mice; H&E results showed that kidney tissue damage and tissue fibrosis were reduced in kidney-injured mice under quercetin. The mitochondrial swollen structure was destroyed by doxorubicin, while the mitochondrial structure was restored under quercetin. The levels of abnormal apoptotic proteins Bax and Bcl-2 were regulated to normal by quercetin. The high expression of Ang II caused by doxorubicin was down-regulated by quercetin. Abnormal inflammatory factors caused by doxorubicin were reversed by quercetin. Western blot experiments showed that quercetin regulated the protein levels of AKT1 and Raf/MEK/ERK and inhibited the detrimental effects of doxorubicin.

CONCLUSION

Quercetin may mitigate doxorubicin-induced kidney injury in mice by regulating renal cell inflammatory factors and Raf/MEK/ERK signaling pathway through AKT1 to promote recovery of renal function.