Metformin alleviates cholestasis-associated nephropathy through regulating oxidative stress and mitochondrial function

Sex-Specific Mechanisms of Fluoride-Induced Gonadal Injury: A Multi-Omics Investigation into Reproductive Toxicity and Gut Microbiota Disruption

Fluoride, a common agricultural additive used to enhance plant resilience and pest control, poses toxicity risks when exposure surpasses safe thresholds, affecting ecosystems and human health. While its reproductive toxicity is recognized, the sex-specific and cross-generational effects remain underexplored. To address this gap, we employed an integrative approach combining transcriptomics (next-generation sequencing (NGS)), bioinformatic network analysis, gut microbiota sequencing, and in vivo functional assays. ICR mice (F0 generation), both male and female, were exposed to fluoride (100 mg/L in drinking water) for 35 days, continuing through gestation and offspring weaning. Our transcriptomic analysis revealed significant upregulation of autophagy (via the PI3K-AKT-mTOR pathway) and oxidative stress-induced mitochondrial dysfunction in gonadal tissue, with more pronounced effects observed in males. Further integrated analyses of transcriptomic and metabolomic data, supported by in vivo experiments, highlighted oxidative stress, mitochondrial dysfunction, and PI3K-AKT-mTOR pathway activation with stronger effects in males. The principal component analysis confirmed sex-specific transcriptome alterations, with males showing more substantial disruption. Additionally, 16S rRNA sequencing identified significant gut dysbiosis, particularly in males, with an increased Firmicutes/Bacteroidetes ratio and higher abundances of Oscillospirales and Anaerovoracaceae. Moreover, our study identified significant correlations between specific gut microbiota (e.g., Firmicutes, Proteobacteria) and autophagy, oxidative stress, and mitochondrial dysfunction pathways, with notable sex-dependent differences. These findings suggest that gut microbiota may play a critical role in modulating fluoride-induced reproductive toxicity, particularly through their effects on oxidative stress and cellular homeostasis. The breakdown of the gut barrier and elevated serum/gonadal lipopolysaccharide (LPS) levels in fluoride-treated mice further established a link between gut dysbiosis and fluoride-induced reproductive toxicity. These findings underscore the importance of considering sex differences in xenobiotic-induced reproductive and developmental toxicity.

The correlation between blood lipids and intrahepatic cholestasis syndrome during pregnancy

BACKGROUND

To analyse changes in lipid levels during the development of intrahepatic cholestasis of pregnancy (ICP) and identify new biomarkers for predicting ICP.

METHODS

A retrospective case-control study was conducted to analyse 473 pregnant women who underwent regular prenatal examinations and delivered at the Women and Children's Hospital, School of Medicine, Xiamen University, between June 2020 and June 2023, including 269 normal pregnancy controls and 204 pregnant women with cholestasis.

RESULTS

Patients with ICP with gestational diabetes mellitus (GDM) have lower high-density lipoprotein (HDL) levels than in those without GDM. Total bile acid (TBA) levels were significantly higher in pregnant women with GDM than those without. The apolipoprotein A (APOA) level was lower in patients with ICP and hypothyroidism than those without hypothyroidism. TBA levels were significantly higher in pregnant women with hypothyroidism than those without. Triglyceride (TG) levels were significantly higher in patients with preeclampsia (PE) than those without. HDL and APOA levels were lower in women with ICP complicated by preterm delivery than those with normal delivery. The AUC (area under the curve) of the differential diagnosis of cholestasis of pregnancy for the APOA/APOB (apolipoprotein B) ratio was 0.727, with a sensitivity of 85.9% and specificity of 47.5%.

CONCLUSIONS

The results suggested that dyslipidaemia is associated with an increased risk of ICP and its complications. The timely detection of blood lipid and bile acid levels can assist in the diagnosis of ICP and effectively prevent ICP and other complications.

The Footprints of Mitochondrial Fission and Apoptosis in Fluoride-Induced Renal Dysfunction

Fluoride (F) is widely distributed in the environment and poses serious health risks to humans and animals. Although a good body of literature demonstrates a close relationship between F content and renal system performance, there is no satisfactory information on the involved intracellular routes. Hence, this study used histopathology and mitochondrial fission to explore fluorine-induced nephrotoxicity further. For this purpose, mice were exposed to the F ion (0, 25, 50, 100 mg/L) for 90 days. The effects of different F levels on renal pathomorphology and ion metabolism were assessed using hematoxylin and eosin (H&E), periodic acid-Schiff stain (PAS), periodic acid-silver methenamine (PASM), Prussian blue (PB), and alkaline phosphatase (ALP) staining. The results showed that F could lead to glomerular atrophy, tubular degeneration, and vacuolization. Meanwhile, F also could increase glomerular and tubular glycoproteins; made thickening of the renal capsule membrane and thickening of the tubular basement membrane; led to the accumulation of iron ions in the tubules; and increased in glomerular alp and decreased tubular alp. Concomitantly, IHC results showed that F significantly upregulated the expression levels of mitochondrial fission-related proteins, including mitochondrial fission factor (Mff), fission 1 (Fis1), and mitochondrial dynamics proteins of 49 kDa (MiD49) and 51 kDa (MiD51), ultimately caused apoptosis. To sum up, excessive fluorine has a strong nephrotoxicity effect, disrupting the balance of mitochondrial fission and fusion, interfering with the process of mitochondrial fission, and then causing damage to renal tissue structure and apoptosis.

Molecular insights into experimental models and therapeutics for cholestasis

Cholestatic liver disease (CLD) is a range of conditions caused by the accumulation of bile acids (BAs) or disruptions in bile flow, which can harm the liver and bile ducts. To investigate its pathogenesis and treatment, it is essential to establish and assess experimental models of cholestasis, which have significant clinical value. However, owing to the complex pathogenesis of cholestasis, a single modelling method can merely reflect one or a few pathological mechanisms, and each method has its adaptability and limitations. We summarize the existing experimental models of cholestasis, including animal models, gene-knockout models, cell models, and organoid models. We also describe the main types of cholestatic disease simulated clinically. This review provides an overview of targeted therapy used for treating cholestasis based on the current research status of cholestasis models. In addition, we discuss the respective advantages and disadvantages of different models of cholestasis to help establish experimental models that resemble clinical disease conditions. In sum, this review not only outlines the current research with cholestasis models but also projects prospects for clinical treatment, thereby bridging basic research and practical therapeutic applications.

Evaluating the protective effect of metformin against diclofenac-induced oxidative stress and hepatic damage: In vitro and in vivo studies

Diclofenac (DIC) is one of the most commonly prescribed non-steroidal anti-inflammatory drugs and has been shown to cause oxidative stress and liver injury. The current study investigated protective effects of metformin against DIC-induced hepatic toxicity in both in vitro and in vivo models. For the in vitro study, HepG2 cells were exposed to DIC in the presence or absence of metformin. The effect of metformin on cell viability was evaluated by MTT assay. Oxidative stress parameters (malondialdehyde (MDA), total thiol molecules (TTM), and total antioxidant capacity (TAC)) were assessed. For the in vivo study, thirty-six male Wistar rats were randomly divided into 6 groups. These groups were normal saline, metformin (200 mg/kg), DIC (50 mg/kg/day), DIC + metformin (50, 100, and 200 mg/kg/day). Histopathological studies and serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), albumin, direct and total bilirubin were measured. Also, oxidative stress parameters were assessed in liver tissue. Furthermore, expression of glutathione peroxidase (GPX)-1, -3, and -4, catalase (CAT), superoxide dismutase (SOD)-1, and -3 was examined using the real-time PCR method in hepatic tissue. In the in vitro study, metformin significantly prevented DIC-induced loss in cell viability in HepG2 cells. Metformin markedly reduced DIC-induced elevation of MDA levels and increased the TAC and TTM levels. In the in vivo study, metformin significantly prevented DIC-induced changes in hematological and histological markers. Administration of metformin significantly improved oxidative stress parameters in liver tissue. In addition, metformin increased the expression of antioxidant enzymes. Our results suggest that metformin exerts a significant protective effect against DIC-induced hepatic toxicity.

Nrf2/HO-1 as a therapeutic target in renal fibrosis

Chronic kidney disease (CKD) is one of the most prevalent chronic diseases and affects between 10 and 14 % of the world's population. The World Health Organization estimates that by 2040, the disease will be fifth in prevalence. End-stage CKD is characterized by renal fibrosis, which can eventually lead to kidney failure and death. Renal fibrosis develops due to multiple injuries and involves oxidative stress and inflammation. In the human body, nuclear factor erythroid 2-related factor 2 (Nrf2) plays an important role in the expression of antioxidant, anti-inflammatory, and cytoprotective genes, which prevents oxidative stress and inflammation damage. Heme oxygenase (HO-1) is an inducible homolog influenced by heme products and after exposure to cellular stress inducers such as oxidants, inflammatory chemokines/cytokines, and tissue damage as an outcome or downstream of Nrf2 activation. HO-1 is known for its antioxidative properties, which play an important role in regulating oxidative stress. In renal diseases-induced tissue fibrosis and xenobiotics-induced renal fibrosis, Nrf2/HO-1 has been targeted with promising results. This review summarizes these studies and highlights the interesting bioactive compounds that may assist in attenuating renal fibrosis mediated by HO-1 activation. In conclusion, Nrf2/HO-1 signal activation could have a renoprotective effect strategy against CKD caused by oxidative stress, inflammation, and consequent renal fibrosis.

Hepatic encephalopathy complications are diminished by piracetam via the interaction between mitochondrial function, oxidative stress, inflammatory response, and locomotor activity

Background

of the study: Hepatic encephalopathy (HE) is a complication in which brain ammonia (NH4+) levels reach critically high concentrations because of liver failure. HE could lead to a range of neurological complications from locomotor and behavioral disturbances to coma. Several tactics have been established for subsiding blood and brain NH4+. However, there is no precise intervention to mitigate the direct neurological complications of NH4+.

Purpose

It has been found that oxidative stress, mitochondrial damage, and neuro-inflammation play a fundamental role in NH4+ neurotoxicity. Piracetam is a drug used clinically in neurological complications such as stroke and head trauma. Piracetam could significantly diminish oxidative stress and improve brain mitochondrial function.

Research methods

In the current study, piracetam (100 and 500 mg/kg, oral) was used in a mice model of HE induced by thioacetamide (TA, 800 mg/kg, single dose, i.p).

Results

Significant disturbances in animals' locomotor activity, along with increased oxidative stress biomarkers, including reactive oxygen species formation, protein carbonylation, lipid peroxidation, depleted tissue glutathione, and decreased antioxidant capacity, were evident in the brain of TA-treated mice. Meanwhile, mitochondrial permeabilization, mitochondrial depolarization, suppression of dehydrogenases activity, and decreased ATP levels were found in the brain of the TA group. The level of pro-inflammatory cytokines was also significantly high in the brain of HE animals.

Conclusion

It was found that piracetam significantly enhanced mice's locomotor activity, blunted oxidative stress biomarkers, decreased inflammatory cytokines, and improved mitochondrial indices in hyperammonemic mice. These data suggest piracetam as a neuroprotective agent which could be repurposed for the management of HE.

Metformin beyond an anti-diabetic agent: A comprehensive and mechanistic review on its effects against natural and chemical toxins

In addition to the anti-diabetic effect of metformin, a growing number of studies have shown that metformin has some exciting properties, such as anti-oxidative capabilities, anticancer, genomic stability, anti-inflammation, and anti-fibrosis, which have potent, that can treat other disorders other than diabetes mellitus. We aimed to describe and review the protective and antidotal efficacy of metformin against biologicals, chemicals, natural, medications, pesticides, and radiation-induced toxicities. A comprehensive search has been performed from Scopus, Web of Science, PubMed, and Google Scholar databases from inception to March 8, 2023. All in vitro, in vivo, and clinical studies were considered. Many studies suggest that metformin affects diseases other than diabetes. It is a radioprotective and chemoprotective drug that also affects viral and bacterial diseases. It can be used against inflammation-related and apoptosis-related abnormalities and against toxins to lower their effects. Besides lowering blood sugar, metformin can attenuate the effects of toxins on body weight, inflammation, apoptosis, necrosis, caspase-3 activation, cell viability and survival rate, reactive oxygen species (ROS), NF-κB, TNF-α, many interleukins, lipid profile, and many enzymes activity such as catalase and superoxide dismutase. It also can reduce the histopathological damages induced by many toxins on the kidneys, liver, and colon. However, clinical trials and human studies are needed before using metformin as a therapeutic agent against other diseases.

Pulmonary inflammation, oxidative stress, and fibrosis in a mouse model of cholestasis: the potential protective properties of the dipeptide carnosine

Cholestasis is a clinical complication that primarily influences the liver. However, it is well known that many other organs could be affected by cholestasis. Lung tissue is a major organ influenced during cholestasis. Cholestasis-induced lung injury could induce severe complications such as respiratory distress, serious pulmonary infections, and tissue fibrosis. Unfortunately, there is no specific pharmacological intervention against this complication. Several studies revealed that oxidative stress and inflammatory response play a role in cholestasis-induced lung injury. Carnosine (CARN) is a dipeptide found at high concentrations in different tissues of humans. CARN's antioxidant and antiinflammatory properties are repeatedly mentioned in various experimental models. This study aimed to assess the role of CARN on cholestasis-induced lung injury. Rats underwent bile duct ligation (BDL) to induce cholestasis. Broncho-alveolar lavage fluid (BALF) levels of inflammatory cells, pro-inflammatory cytokines, and immunoglobulin were monitored at scheduled intervals (7, 14, and 28 days after BDL). Moreover, lung tissue histopathological alterations and biomarkers of oxidative stress were evaluated. A significant increase in BALF inflammatory cells, TNF-α, IL-1β, IL-6, and immunoglobulin-G (IgG) was detected in the BALF of BDL rats. Moreover, lung tissue histopathological changes, collagen deposition, increased TGF-β, and elevated levels of oxidative stress biomarkers were evident in cholestatic animals. It was found that CARN (100 and 500 mg/kg, i.p.) significantly alleviated lung oxidative stress biomarkers, inflammatory response, tissue fibrosis, and histopathological alterations. These data indicate the potential protective properties of CARN in the management of cholestasis-induced pulmonary damage. The effects of CARN on inflammatory response and oxidative stress biomarkers seems to play a crucial role in its protective properties in the lung of cholestatic animals.

Glycine protects the male reproductive system against lead toxicity via alleviating oxidative stress, preventing sperm mitochondrial impairment, improving kinematics of sperm, and blunting the downregulation of enzymes involved in the steroidogenesis

Lead (Pb) is a highly toxic heavy metal widely dispersed in the environment because of human industrial activities. Many studies revealed that Pb could adversely affect several organs, including the male reproductive system. Pb-induced reproductive toxicity could lead to infertility. Thus, finding safe and clinically applicable protective agents against this complication is important. It has been found that oxidative stress plays a fundamental role in the pathogenesis of Pb-induced reprotoxicity. Glycine is the simplest amino acid with a wide range of pharmacological activities. It has been found that glycine could attenuate oxidative stress and mitochondrial impairment in various experimental models. The current study was designed to evaluate the role of glycine in Pb-induced reproductive toxicity in male mice. Male BALB/c mice received Pb (20 mg/kg/day; gavage; 35 consecutive days) and treated with glycine (250 and 500 mg/kg/day; gavage; 35 consecutive days). Then, reproductive system weight indices, biomarkers of oxidative stress in the testis and isolated sperm, sperm kinetic, sperm mitochondrial indices, and testis histopathological alterations were monitored. A significant change in testis, epididymis, and Vas deferens weight was evident in Pb-treated animals. Markers of oxidative stress were also significantly increased in the testis and isolated sperm of the Pb-treated group. A significant disruption in sperm kinetic was also evident when mice received Pb. Moreover, Pb exposure caused significant deterioration in sperm mitochondrial indices. Tubular injury, tubular desquamation, and decreased spermatogenic index were histopathological alterations detected in Pb-treated mice. It was found that glycine significantly blunted oxidative stress markers in testis and sperm, improved sperm mitochondrial parameters, causing considerable higher velocity-related indices (VSL, VCL, and VAP) and percentages of progressively motile sperm, and decreased testis histopathological changes in Pb-exposed animals. These data suggest glycine as a potential protective agent against Pb-induced reproductive toxicity. The effects of glycine on oxidative stress markers and mitochondrial function play a key role in its protective mechanism.

Taurine mitigates the development of pulmonary inflammation, oxidative stress, and histopathological alterations in a rat model of bile duct ligation

Lung injury is a significant complication associated with cholestasis/cirrhosis. This problem significantly increases the risk of cirrhosis-related morbidity and mortality. Hence, finding effective therapeutic options in this field has significant clinical value. Severe inflammation and oxidative stress are involved in the mechanism of cirrhosis-induced lung injury. Taurine (TAU) is an abundant amino acid with substantial anti-inflammatory and antioxidative properties. The current study was designed to evaluate the role of TAU in cholestasis-related lung injury. For this purpose, bile duct ligated (BDL) rats were treated with TAU (0.5 and 1% w: v in drinking water). Significant increases in the broncho-alveolar lavage fluid (BALF) level of inflammatory cells (lymphocytes, neutrophils, basophils, monocytes, and eosinophils), increased IgG, and TNF-α were detected in the BDL animals (14 and 28 days after the BDL surgery). Alveolar congestion, hemorrhage, and fibrosis were the dominant pulmonary histopathological changes in the BDL group. Significant increases in the pulmonary tissue biomarkers of oxidative stress, including reactive oxygen species formation, lipid peroxidation, increased oxidized glutathione levels, and decreased reduced glutathione, were also detected in the BDL rats. Moreover, significant myeloperoxidase activity and nitric oxide levels were seen in the lung of BDL rats. It was found that TAU significantly blunted inflammation, alleviated oxidative stress, and mitigated lung histopathological changes in BDL animals. These data suggest TAU as a potential protective agent against cholestasis/cirrhosis-related lung injury.

The Role of Mitochondrial Impairment and Oxidative Stress in the Pathogenesis of Lithium-Induced Reproductive Toxicity in Male Mice

Lithium (Li+) is prescribed against a wide range of neurological disorders. Besides its excellent therapeutic properties, there are several adverse effects associated with Li+. The impact of Li+ on renal function and diabetes insipidus is the most common adverse effect of this drug. On the other hand, infertility and decreased libido is another complication associated with Li+. It has been found that sperm indices of functionality, as well as libido, is significantly reduced in Li+-treated men. These adverse effects might lead to drug incompliance and the cessation of drug therapy. Hence, the main aims of the current study were to illustrate the mechanisms of adverse effects of Li+ on the testis tissue, spermatogenesis process, and hormonal changes in two experimental models. In the in vitro experiments, Leydig cells (LCs) were isolated from healthy mice, cultured, and exposed to increasing concentrations of Li+ (0, 10, 50, and 100 ppm). In the in vivo section of the current study, mice were treated with Li+ (0, 10, 50, and 100 ppm, in drinking water) for five consecutive weeks. Testis and sperm samples were collected and assessed. A significant sign of cytotoxicity (LDH release and MTT assay), along with disrupted testosterone biosynthesis, impaired mitochondrial indices (ATP level and mitochondrial depolarization), and increased biomarkers of oxidative stress were detected in LCs exposed to Li+. On the other hand, a significant increase in serum and testis Li+ levels were detected in drug-treated mice. Moreover, ROS formation, LPO, protein carbonylation, and increased oxidized glutathione (GSSG) were detected in both testis tissue and sperm specimens of Li+-treated mice. Several sperm anomalies were also detected in Li+-treated animals. On the other hand, sperm mitochondrial indices (mitochondrial dehydrogenases activity and ATP levels) were significantly decreased in drug-treated groups where mitochondrial depolarization was increased dose-dependently. Altogether, these data mention oxidative stress and mitochondrial impairment as pivotal mechanisms involved in Li+-induced reproductive toxicity. Therefore, based on our previous publications in this area, therapeutic options, including compounds with high antioxidant properties that target these points might find a clinical value in ameliorating Li+-induced adverse effects on the male reproductive system.

Moderation of doxorubicin-induced nephrotoxicity in Wistar rats by aqueous leaf-extracts of Chromolaena odorata and Tridax procumbens

BACKGROUND

The major draw-back of doxorubicin's use in chemotherapy is its toxicity on various organs including the kidneys. This study investigated the potential protective role of aqueous leaf-extracts of Chromolaena odorata and Tridax procumbens against nephrotoxicity induced by doxorubicin.

METHODS

To this end, their impact on plasma biomarkers of kidney function, as well as renal lipid profile, biomarkers of oxidative stress, electrolyte profile and activities of renal ATPases was monitored in doxorubicin treated rats. Metformin (250 mg/kg body weight, orally) and the extracts (50, 75 and 100 mg/kg, orally) were daily administered for 14 days; while nephrotoxicity was induced with doxorubicin (15 mg/kg, intra-peritioneally), once on the 12th day of study.

RESULTS

The plasma concentrations of creatinine, and urea; as well as the renal malondialdehyde, cholesterol, calcium and sodium concentrations in the Test control, were significantly (P < .05) higher than those of all the other groups. However, the renal concentrations of ascorbic acid, chloride, magnesium and potassium, and the renal activities of catalase, glutathione peroxidase superoxide dismutase, Ca2+-ATPase, Mg2+-ATPase and Na+,K+-ATPase in the Test control were significantly (P < .05) lower than those of all the other groups.

CONCLUSIONS

Pre-treatment with the extracts and metformin boosted endogenous antioxidants, and prevented doxorubicin-induced renal damage, as indicated by the attenuation of doxorubicin-induced renal oxidative stress, as well as the attenuation of doxorubicin-induced adverse alterations in renal cholesterol, ATPases and electrolyte balance, and plasma biomarkers of kidney function, and keeping them at near-normal values.