Renoprotective effect of nifuroxazide in diabetes-induced nephropathy: impact on NFκB, oxidative stress, and apoptosis

Molecular mechanisms underlying methotrexate-induced intestinal injury and protective strategies

Methotrexate (MTX) is a folic acid reductase inhibitor that manages various malignancies as well as immune-mediated inflammatory chronic diseases. Despite being frequently prescribed, MTX's severe multiple toxicities can occasionally limit its therapeutic potential. Intestinal toxicity is a severe adverse effect associated with the administration of MTX, and patients are significantly burdened by MTX-provoked intestinal mucositis. However, the mechanism of such intestinal toxicity is not entirely understood, mechanistic studies demonstrated oxidative stress and inflammatory reactions as key factors that lead to the development of MTX-induced intestinal injury. Besides, MTX causes intestinal cells to express pro-inflammatory cytokines like interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α), which activate nuclear factor-kappa B (NF-κB). This is followed by the activation of the Janus kinase/signal transducer and activator of the transcription3 (JAK/STAT3) signaling pathway. Moreover, because of its dual anti-inflammatory and antioxidative properties, nuclear factor erythroid-2-related factor 2/heme oxygenase-1 (Nrf2/HO-1) has been considered a critical signaling pathway that counteracts oxidative stress in MTX-induced intestinal injury. Several agents have potential protective effects in counteracting MTX-provoked intestinal injury such as omega-3 polyunsaturated fatty acids, taurine, umbelliferone, vinpocetine, perindopril, rutin, hesperidin, lycopene, quercetin, apocynin, lactobacillus, berberine, zinc, and nifuroxazide. This review aims to summarize the potential redox molecular mechanisms of MTX-induced intestinal injury and how they can be alleviated. In conclusion, studying these molecular pathways might open the way for early alleviation of the intestinal damage and the development of various agent plans to attenuate MTX-mediated intestinal injury.

Leflunomide-induced cardiac injury in adult male mice and bioinformatic approach identifying Nrf2/NF-κb signaling interplay

Leflunomide (LFND) is an immunosuppressive and immunomodulatory disease-modifying antirheumatic drug (DMARD) that was approved for treating rheumatoid arthritis. LFND-induced cardiotoxicity was not fully investigated since its approval. We investigated the cardiac injury in male mice and identified the role of nuclear factor erythroid 2-related factor 2/nuclear factor-κ B (Nrf2/NF-κB) signaling. Male albino mice were assigned into five groups as control, vehicle, and LFND (2.5, 5, and 10 mg/kg). We investigated cardiac enzymes, histopathology, and the mRNA expression of Nrf2, NF-κB, BAX, and tumor necrosis factor-α (TNF-α). The bioinformatic study identified the interaction between LFND and Nrf2/NF-κB signaling; this was confirmed by amelioration in mRNA expression (0.5- to 0.34-fold decrease in Nrf2 and 2.6- to 4.61-fold increases in NF-κB genes) and increased (1.76- and 2.625-fold) serum creatine kinase (CK) and 1.38- and 2.33-fold increases in creatine kinase-MB (CK-MB). Histopathological results confirmed the dose-dependent effects of LFND on cardiac muscle structure in the form of cytoplasmic, nuclear, and vascular changes in addition to increased collagen deposits and apoptosis which were increased compared to controls especially with LFND 10 mg/kg. The current study elicits the dose-dependent cardiac injury induced by LFND administration and highlights, for the first time, dysregulation in Nrf2/NF-κB signaling.

Nifuroxazide attenuates indomethacin-induced renal injury by upregulating Nrf2/HO-1 and cytoglobin and suppressing NADPH-oxidase, NF-κB, and JAK-1/STAT3 signals

Indomethacin (INDO) is an NSAID with remarkable efficacy and widespread utilization for alleviating pain. Nevertheless, renal function impairment is an adverse reaction linked to INDO usage. Nifuroxazide (NFX), an oral nitrofuran antibiotic, is frequently employed as an intestinal anti-infective agent. Our study aimed to investigate the renoprotective effects of NFX against INDO-induced nephrotoxicity and explore the protection mechanisms. Four groups of rats were allocated to (I) the normal control, (II) the NFX-treated (50 mg/kg), (III) INDO control (20 mg/kg), and (IV) NFX + INDO. NFX attenuates renal impairment in INDO-induced renal injury, proved by decreasing serum levels of urea, creatinine, uric acid, and NGAL while the albumin was elevated. NFX mitigates renal oxidative stress by decreasing MDA levels and restoring the antioxidants' GSH and SOD levels mediated by upregulating Nrf2, HO-1, and cytoglobin pathways. NFX mitigated renal inflammation and effectively decreased MPO, IL-1β, and TNF-α levels in the rat's kidney mediated by significant downregulation of NADPH-oxidase and NF-κB expression and suppression of JAK-1 and STAT3 phosphorylation. NFX mitigates renal apoptosis by decreasing the expression of cleaved caspase-3 expression. In conclusion, NFX treatment prevents INDO nephrotoxicity by regulating Nrf2/HO-1, cytoglobin, NADPH-oxidase, NF-κB, and JAK-1/STAT3 signals.

Oxidative Stress: A Culprit in the Progression of Diabetic Kidney Disease

Diabetic kidney disease (DKD) is the principal culprit behind chronic kidney disease (CKD), ultimately developing end-stage renal disease (ESRD) and necessitating costly dialysis or kidney transplantation. The limited therapeutic efficiency among individuals with DKD is a result of our finite understanding of its pathogenesis. DKD is the result of complex interactions between various factors. Oxidative stress is a fundamental factor that can establish a link between hyperglycemia and the vascular complications frequently encountered in diabetes, particularly DKD. It is crucial to recognize the essential and integral role of oxidative stress in the development of diabetic vascular complications, particularly DKD. Hyperglycemia is the primary culprit that can trigger an upsurge in the production of reactive oxygen species (ROS), ultimately sparking oxidative stress. The main endogenous sources of ROS include mitochondrial ROS production, NADPH oxidases (Nox), uncoupled endothelial nitric oxide synthase (eNOS), xanthine oxidase (XO), cytochrome P450 (CYP450), and lipoxygenase. Under persistent high glucose levels, immune cells, the complement system, advanced glycation end products (AGEs), protein kinase C (PKC), polyol pathway, and the hexosamine pathway are activated. Consequently, the oxidant-antioxidant balance within the body is disrupted, which triggers a series of reactions in various downstream pathways, including phosphoinositide 3-kinase/protein kinase B (PI3K/Akt), transforming growth factor beta/p38-mitogen-activated protein kinase (TGF-β/p38-MAPK), nuclear factor kappa B (NF-κB), adenosine monophosphate-activated protein kinase (AMPK), and the Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling. The disease might persist even if strict glucose control is achieved, which can be attributed to epigenetic modifications. The treatment of DKD remains an unresolved issue. Therefore, reducing ROS is an intriguing therapeutic target. The clinical trials have shown that bardoxolone methyl, a nuclear factor erythroid 2-related factor 2 (Nrf2) activator, blood glucose-lowering drugs, such as sodium-glucose cotransporter 2 inhibitors, and glucagon-like peptide-1 receptor agonists can effectively slow down the progression of DKD by reducing oxidative stress. Other antioxidants, including vitamins, lipoic acid, Nox inhibitors, epigenetic regulators, and complement inhibitors, present a promising therapeutic option for the treatment of DKD. In this review, we conduct a thorough assessment of both preclinical studies and current findings from clinical studies that focus on targeted interventions aimed at manipulating these pathways. We aim to provide a comprehensive overview of the current state of research in this area and identify key areas for future exploration.

Nifuroxazide repurposing for protection from diabetes-induced retinal injury in rats: Implication of oxidative stress and JAK/STAT3 axis

The prevalence of diabetes mellitus (DM) is alarmingly increasing worldwide. Diabetic retinopathy (DR) is a prevailing DM microvascular complication, representing the major cause of blindness in working-age population. Inflammation is a crucial player in DR pathogenesis. JAK/STAT3 axis is a pleotropic cascade that modulates diverse inflammatory events. Nifuroxazide (Nifu) is a commonly used oral antibiotic with reported JAK/STAT3 inhibition activity. The present study investigated the potential protective effect of Nifu against diabetes-induced retinal injury. Effect of Nifu on oxidative stress, JAK/STAT3 axis and downstream inflammatory mediators has been also studied. Diabetes was induced in Sprague Dawley rats by single intraperitoneal injection of streptozotocin (50 mg/kg). Animals were assigned into four groups: normal, Nifu control, DM, and DM + Nifu. Nifu was orally administrated at 25 mg/kg/day for 8 weeks. The effects of Nifu on oxidative stress, JAK/STAT3 axis proteins, inflammatory factors, tight junction proteins, histological, and ultrastructural alterations were evaluated using spectrophotometry, gene and protein analyses, and histological studies. Nifu administration to diabetic rats attenuated histopathological and signs of retinal injury. Additionally, Nifu attenuated retinal oxidative stress, inhibited JAK and STAT3 phosphorylation, augmented the expression of STAT3 signaling inhibitor SOCS3, dampened the expression of transcription factor of inflammation NF-κB, and inflammatory cytokine TNF-α. Collectively, the current study indicated that Nifu alleviated DR progression in diabetic rats, suggesting beneficial retino-protective effect. This can be attributed to blocking JAK/STAT3 axis in retinal tissues with subsequent amelioration of oxidative stress and inflammation.

The enteroprotective effect of nifuroxazide against methotrexate-induced intestinal injury involves co-activation of PPAR-γ, SIRT1, Nrf2, and suppression of NF-κB and JAK1/STAT3 signals

Methotrexate (MTX) has long manifested therapeutic efficacy in several neoplastic and autoimmune disorders. However, MTX-associated intestinal toxicity restricts the continuation of treatment. Nifuroxazide (NIF) is an oral antibiotic approved for gastrointestinal infections as an effective antidiarrheal agent with a high safety profile. The current study was designed to explore the potential efficacy of NIF in alleviating intestinal toxicity associated with MTX chemotherapy with the elucidation of the proposed molecular mechanisms. Rats were administered NIF (50 mg/kg; p.o.) for ten days. On day five, a single i.p. injection of MTX (20 mg/kg) was given to induce intestinal intoxication. At the end of the experiment, duodenal tissue samples were isolated for biochemical, Western blotting, immunohistochemical (IHC), and histopathological analysis via H&E, PSA, and Alcian blue stains. NIF showed antioxidant enteroprotective effects against MTX intestinal intoxication through enhanced expression of the redox-sensitive signals of PPAR-γ, SIRT1, and Nrf2 estimated by IHC. Moreover, NIF down-regulated the pro-inflammatory cytokines (TNF-α, IL-1β, IL-6), NF-κB protein expression, and the phosphorylation of JAK1/STAT3 proteins, leading to mitigation of intestinal inflammation. In accordance, the histological investigation revealed that NIF ameliorated the intestinal pathological changes, preserved the goblet cells, and reduced the inflammatory cells infiltration. Therefore, NIF could be a promising candidate for adjunctive therapy with MTX to mitigate the associated intestinal injury and increase its tolerability.

Anti-aging effect of nifuroxazide on skin changes of aged male rat models via modulating immunoreactivity of IL-6/NF-κB/Caspase-3

PURPOSE

To evaluate nifuroxazide's (NIF's) anti-aging characteristics in a skin-aging rat model for the first time in order to create effective preventive measures and anti-aging skin therapies.

MATERIALS AND METHODS

Thirty randomly selected aged male rats were assorted into three equal groups; aged control group, treated NIF I, aged rats were treated with NIF (10mg/kg, orally once daily for 14 consecutive days), and treated NIF II, aged rats were treated with NIF (20mg/kg, orally once daily for 14 consecutive days). Skin samples were obtained from the dorsal skin of the aged male rats and processed for tissue biochemical MDA, histological (Hx&E and Masson's Trichrome stains), and immunohistochemical (IL-6, NF-κB, and caspase-3) analysis.

RESULTS

Group I aged male albino rat skin illustrated evident distorted epidermis and dermis, disorganization of collagen fibers with marked multiple spaces of collagen fibers loss in the dermis, marked reduction of total epidermal thickness and mean area percent of collagen fibers, elevated tissue MDA level and strong positive IL-6, NF-κB, and caspase-3 immune reaction. The anti-aging benefits of NIF on skin aging are demonstrated by a marked improvement in histological alterations in the form of a well-organized epidermis and dermis, most collagen fibers in the dermis appear closely packed, significant elevation of total epidermal thickness and mean area percent of collagen fibers, a significant decrease of tissue MDA level, and immunoexpression of the inflammatory markers, IL-6, and NF-κB, and the apoptotic marker caspase-3.

CONCLUSIONS

This study found that group III, which received 20mg/kg of NIF, experienced more pronounced and noticeable improvements in skin aging than group II, which received 10mg/kg of NIF.

JAK/STAT signaling in diabetic kidney disease

Diabetic kidney disease (DKD) is the most important microvascular complication of diabetes and the leading cause of end-stage renal disease (ESRD) worldwide. The Janus kinase/signal transducer and activator of the transcription (JAK/STAT) signaling pathway, which is out of balance in the context of DKD, acts through a range of metabolism-related cytokines and hormones. JAK/STAT is the primary signaling node in the progression of DKD. The latest research on JAK/STAT signaling helps determine the role of this pathway in the factors associated with DKD progression. These factors include the renin-angiotensin system (RAS), fibrosis, immunity, inflammation, aging, autophagy, and EMT. This review epitomizes the progress in understanding the complicated explanation of the etiologies of DKD and the role of the JAK/STAT pathway in the progression of DKD and discusses whether it can be a potential target for treating DKD. It further summarizes the JAK/STAT inhibitors, natural products, and other drugs that are promising for treating DKD and discusses how these inhibitors can alleviate DKD to explore possible potential drugs that will contribute to formulating effective treatment strategies for DKD in the near future.

Pharmacological updates of nifuroxazide: Promising preclinical effects and the underlying molecular mechanisms

Nifuroxazide (NFX) is a safe nitrofuran antibacterial drug used clinically to treat acute diarrhea and infectious traveler diarrhea or colitis. Recent studies revealed that NFX displays multiple pharmacological effects, including anticancer, antioxidant, and anti-inflammatory effects. NFX has potential roles in inhibiting thyroid, breast, lung, bladder, liver, and colon cancers and osteosarcoma, melanoma, and others mediated by suppressing STAT3 as well as ALDH1, MMP2, MMP9, Bcl2 and upregulating Bax. Moreover, it has promising effects against sepsis-induced organ injury, hepatic disorders, diabetic nephropathy, ulcerative colitis, and immune disorders. These promising effects appear to be mediated by suppressing STAT3 as well as NF-κB, TLR4, and β-catenin expressions and effectively decreasing downstream cytokines TNF-α, IL-1β, and IL-6. Our review summarizes the available studies on the molecular biological mechanisms of NFX in cancer and other diseases and it is recommended to translate the studies in experimental animals and cultured cells and repurpose NFX in various diseases for scientific evidence based on human studies.

Metformin suppresses LRG1 and TGFβ1/ALK1-induced angiogenesis and protects against ultrastructural changes in rat diabetic nephropathy

Diabetic nephropathy (DN) has high prevalence and poor prognosis which make it a research priority for scientists. Since metformin, a hypoglycaemic drug, has been found to prolong the survival of mice with DN. This study aims at investigating the molecular mechanisms leading to DN in rats and to explore the role of leucine-rich α-2-glycoprotein-1 (LRG1), activin-like kinase1 (ALK1), and transforming growth factor-β (TGFβ1) in the pathologic alterations seen in DN. The aim was also extended to explore the protective action of metformin against DN in rats and its influence on LRG1and ALK1/TGFβ1 induced renal angiogenesis. 24 male rats were used. Rats were assigned as, the vehicle group, the diabetic control group and diabetic + metformin (100 and 200 mg/kg) groups. Kidney samples were processed for histopathology, immunohistochemistry and biochemical analysis. Bioinformatic analysis of studied proteins was done to determine protein-protein interactions. Metformin reduced serum urea and creatinine significantly, decreased the inflammatory cytokine levels and reduced LRG1, TGFβ1, ALK1 and vascular endothelial growth factor (VEGF) proteins in rat kidneys. Bioinformatic analysis revealed interactions between the studied proteins. Metformin alleviated the histopathological changes observed in the diabetic rats such as the glomerular surface area and increased Bowman's space diameter. Metformin groups showed decreased VEGF immunostaining compared to diabetic group. Metformin shows promising renoprotective effects in diabetic model that was at least partly mediated by downregulation of LRG1 and TGFβ1/ALK1-induced renal angiogenesis. These results further explain the molecular mechanism of metformin in DN management.

Development and Validation of a HPLC–MS/MS Method to Measure Nifuroxazide and Its Application in Healthy and Glioblastoma-Bearing Mice

Nifuroxazide (NAZ), a nitrofuran derivative used to treat diarrhea, has been recently shown to possess anticancer activity. However, its pharmacokinetic profile is poorly known. The pharmacokinetic profile of NAZ was thus investigated in mice using a newly developed method based on high-performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS). We determined the concentrations of NAZ in the plasma and brain tissue of mice treated with the drug. The method proved to be specific, reproducible, precise, and accurate. It also demonstrated high sensitivity, reaching an LOQ in the order of ppb for both matrices, using samples of 100 µL or 0.2 g. The new HPLC–MS/MS assay was successfully applied to study the pharmacokinetics of NAZ after chronic intraperitoneal administration in mice at a dose of 30 mg/kg. One hour after treatment, plasma concentrations of NAZ were in the range of 336–2640 ng/mL. Moreover, unlike the brains of healthy mice or those with healed mechanical injuries, we found that NAZ was able to cross the injured blood–brain barrier of tumor-infiltrated brains. Thus, following i.p. administration, NAZ reaches systemic levels suitable for testing its efficacy in preclinical models of glioblastoma. Overall, these pharmacokinetic data provide robust evidence supporting the repositioning of NAZ as an antitumor drug.

Dapagliflozin, Liraglutide, and Their Combination Attenuate Diabetes Mellitus-Associated Hepato-Renal Injury—Insight into Oxidative Injury/Inflammation/Apoptosis Modulation

In this study, we aim to explore the beneficial therapeutic impacts of dapagliflozin (Dapa), a highly potent, reversible, and selective sodium–glucose cotransporter-2 inhibitor, and liraglutide (Lira), a glucagon-like peptide-1 (GLP-1) receptor agonist, as hypoglycaemic agents for the management of diabetes mellitus (DM), as well as their combination against DM-induced complications, including hepato-renal injury. Indeed, the progression of DM was found to be associated with significant hepatic and renal injury, as confirmed by the elevated biochemical indices of hepatic and renal functions, as well as histopathological examination. Dapa, Lira, and their combination effectively attenuated DM-induced hepatic and renal injury, as confirmed by the recovery of hepatic and renal functional biomarkers. The administration of both drugs significantly reduced the tissue contents of MDA and restored the contents of GSH and catalase activity. Moreover, NF-κB and TNF-α expression at the protein and gene levels was significantly reduced in the liver and the kidney. This was in parallel with the significant reduction in the caspase-3 content in the liver and the kidney, as well as suppressed cleaved caspase-3 expression in the hepatic and renal specimens, as confirmed by immune–histochemical analysis. Notably, the combined Dapa/Lira treatment demonstrated an additive superior hepato-renal protective impact compared with the use of either drug alone. Thus, it appears that Dapa and Lira, through the coordinated modulation of oxidative, inflammatory, and apoptotic signalling, confer a significant hepato-renal protective impact against DM-induced complications and tissue injury.

Nifuroxazide ameliorates pulmonary fibrosis by blocking myofibroblast genesis: a drug repurposing study

Background

Idiopathic pulmonary fibrosis (IPF) is a serious interstitial lung disease with a complex pathogenesis and high mortality. The development of new drugs is time-consuming and laborious; therefore, research on the new use of old drugs can save time and clinical costs and even avoid serious side effects. Nifuroxazide (NIF) was originally used to treat diarrhoea, but more recently, it has been found to have additional pharmacological effects, such as anti-tumour effects and inhibition of inflammatory diseases related to diabetic nephropathy. However, there are no reports regarding its role in pulmonary fibrosis.

Methods

The therapeutic effect of NIF on pulmonary fibrosis in vivo was measured by ELISA, hydroxyproline content, H&E and Masson staining, immunohistochemistry (IHC) and western blot. Immune cell content in lung tissue was also analysed by flow cytometry. NIF cytotoxicity was evaluated in NIH/3T3 cells, human pulmonary fibroblasts (HPFs), A549 cells and rat primary lung fibroblasts (RPLFs) using the MTT assay. Finally, an in vitro cell model created by transforming growth factor-β1 (TGF-β1) stimulation was assessed using different experiments (immunofluorescence, western blot and wound migration assay) to evaluate the effects of NIF on the activation of NIH/3T3 and HPF cells and the epithelial-mesenchymal transition (EMT) and migration of A549 cells.

Results

In vivo, intraperitoneal injection of NIF relieved and reversed pulmonary fibrosis caused by bleomycin (BLM) bronchial instillation. In addition, NIF inhibited the expression of a variety of cellular inflammatory factors and immune cells. Furthermore, NIF suppressed the activation of fibroblasts and EMT of epithelial cells induced by TGF-β1. Most importantly, we used an analytical docking experiment and thermal shift assay to further verify that NIF functions in conjunction with signal transducer and activator of transcription 3 (Stat3). Moreover, NIF inhibited the TGF-β/Smad pathway in vitro and decreased the expression of phosphorylated Stat3 in vitro and in vivo.

Conclusion

Taken together, we conclude that NIF inhibits and reverses pulmonary fibrosis, and these results support NIF as a viable therapeutic option for IPF treatment.

Graphic Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-01946-6.

Nifuroxazide Mitigates Angiogenesis in Ehlrich's Solid Carcinoma: Molecular Docking, Bioinformatic and Experimental Studies on Inhibition of Il-6/Jak2/Stat3 Signaling

Nifuroxazide is an antidiarrheal medication that has promising anticancer activity against diverse types of tumors. The present study tested the anticancer activity of nifuroxazide against Ehrlich’s mammary carcinoma grown in vivo. Furthermore, we investigated the effect of nifuroxazide on IL-6/jak2/STAT3 signaling and the possible impact on tumor angiogenesis. The biological study was supported by molecular docking and bioinformatic predictions for the possible effect of nifuroxazide on this signaling pathway. Female albino mice were injected with Ehrlich carcinoma cells to produce Ehrlich’s solid tumors (ESTs). The experimental groups were as follows: EST control, EST + nifuroxazide (5 mg/kg), and EST + nifuroxazide (10 mg/kg). Nifuroxazide was found to reduce tumor masses (730.83 ± 73.19 and 381.42 ± 109.69 mg vs. 1099.5 ± 310.83) and lessen tumor pathologies. Furthermore, nifuroxazide downregulated IL-6, TNF-α, NFk-β, angiostatin, and Jak2 proteins, and it also reduced tumoral VEGF, as indicated by ELISA and immunohistochemical analysis. Furthermore, nifuroxazide dose-dependently downregulated STAT3 phosphorylation (60% and 30% reductions, respectively). Collectively, the current experiment shed light on the antitumor activity of nifuroxazide against mammary solid carcinoma grown in vivo. The antitumor activity was at least partly mediated by inhibition of IL-6/Jak2/STAT3 signaling that affected angiogenesis (low VEGF and high angiostatin) in the EST. Therefore, nifuroxazide might be a promising antitumor medication if appropriate human studies will be conducted.

Therapeutic role of Azadirachta indica leaves ethanolic extract against diabetic nephropathy in rats neonatally induced by streptozotocin

Diabetic nephropathy (DN) is manifested by chronic loss of renal function due to damage of glomeruli and renal tubules. Therefore, this study is mainly designed to evaluate the therapeutic role of Azadiracta indica (neem) leaves extract as a novel approach for treatment of DN in rats neonatally induced by streptozotocin (STZ). For this study, 40 offspring were selected after parturition and categorized into four groups (n = 10). Group1: control group, group 2: neem leaves extract supplemented group, group 3: diabetic group that injected with a single dose of STZ and group 4: diabetic group treated with neem extract. The results revealed deleterious histological and ultrstructural changes in the renal tissues of diabetic rats. Such changes included atrophied glomeruli, dilated renal cortical tubules and scattered hemorrhage spots, thickening of glomerular basement membrane, expansion of mesangial matrix and pyknotic podocyte. Additionally, the proximal convoluted tubule and distal tubule showed cytoplasmic vacuolation, vacuolated mitochondria, scattered lipid droplets, lost microvilli and disrupted basal lamina and basal infoldings. Moreover, significant decreased levels of serum antioxidants (SOD&CAT) and significant increased levels of serum MDA, urea and creatinine were noticed in diabetic rats. Neem leaves extract successfully alleviated the histological and ultrastructural as well as biochemical changes induced by diabetes.

Regulation of IL-6/STAT-3/Wnt axis by nifuroxazide dampens colon ulcer in acetic acid-induced ulcerative colitis model: Novel mechanistic insight

AIM

Ulcerative colitis (UC) is a common intestinal problem characterized by the diffusion of colon inflammation and immunity dysregulation. Nifuroxazide, a potent STAT-3 inhibitor, exhibits diverse pharmacological properties. The present study aimed to elucidate a novel anti-colitis mechanism of nifuroxazide against the acetic acid-induced UC model.

METHODS

Rats were grouped into control (received vehicle), UC (2 ml of 5% acetic acid by intrarectal infusion), UC plus sulfasalazine (100 mg/kg/day, P.O.), UC plus nifuroxazide (25 mg/kg/day, P.O.), and UC plus nifuroxazide (50 mg/kg/day, P.O.) and lasted for 6 days.

RESULTS

The present study revealed that nifuroxazide significantly reduced UC measures, hematological changes, and histological alteration. In addition, treatment with nifuroxazide significantly down-regulated serum CRP as well as the colonic expressions of MPO, IL-6, TNF-α, TLR-4, NF-κB-p65, JAK1, STAT-3, DKK1 in a dose-dependent manner. Besides, our results showed that the colonic Wnt expression was up-regulated with nifuroxazide treatment. In a dose-dependent manner, nifuroxazide markedly alleviated acetic acid-induced cellular infiltration and improved ulcer healing by increasing intestinal epithelial cell regeneration.

SIGNIFICANCE

Our results collectively indicate that nifuroxazide is an effective anti-colitis agent through regulation of colon inflammation and proliferation via modulation IL-6/STAT-3/Wnt signaling pathway.

Nifuroxazide suppresses UUO-induced renal fibrosis in rats via inhibiting STAT-3/NF-κB signaling, oxidative stress and inflammation

The current work explored the influences of nifuroxazide, an in vivo inhibitor of signal transducer and activator of transcription-3 (STAT-3) activation, on tubulointerstitial fibrosis in rats with obstructive nephropathy using unilateral ureteral obstruction (UUO) model. Thirty-two male Sprague Dawley rats were assigned into 4 groups (n = 8/group) at random. Sham and UUO groups were orally administered 0.5% carboxymethyl cellulose (CMC) (2.5 mL/kg/day), while Sham-NIF and UUO-NIF groups were treated with 20 mg/kg/day of NIF (suspended in 0.5% CMC, orally). NIF or vehicle treatments were started 2 weeks after surgery and continued for further 2 weeks. NIF treatment ameliorated kidney function in UUO rats, where it restored serum creatinine, blood urea, serum uric acid and urinary protein and albumin to near-normal levels. NIF also markedly reduced histopathological changes in tubules and glomeruli and attenuated interstitial fibrosis in UUO-ligated kidneys. Mechanistically, NIF markedly attenuated renal immunoexpression of E-cadherin and α-smooth muscle actin (α-SMA), diminished renal oxidative stress (↓ malondialdehyde (MDA) levels and ↑ superoxide dismutase (SOD) activity), lessened renal protein expression of phosphorylated-STAT3 (p-STAT-3), phosphorylated-Src (p-Src) kinase, the Abelson tyrosine kinase (c-Abl) and phosphorylated nuclear factor-kappaB p65 (pNF-κB p65), decreased renal cytokine levels of transforming growth factor-β1 (TGF-β1), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and monocyte chemoattractant protein-1 (MCP-1) and reduced number of cluster of differentiation 68 (CD68) immunolabeled macrophages in UUO renal tissues, compared to levels in untreated UUO kidneys. Taken together, NIF treatment suppressed interstitial fibrosis in UUO renal tissues, probably via inhibiting STAT-3/NF-κB signaling and attenuating renal oxidative stress and inflammation.

The effect of tropisetron on oxidative stress, SIRT1, FOXO3a, and claudin-1 in the renal tissue of STZ-induced diabetic rats

Tropisetron is a 5-HT3 receptor antagonist that exerts protective effect against DN. The aim of this study was to investigate the possible molecular mechanisms associated with the renoprotective effects of tropisetron in STZ-induced diabetic rats. Animals were subdivided into 5 equal groups; control, tropisetron, diabetes, tropisetron + diabetes, and glibenclamide + diabetes (n = 7). For induction of type 1 diabetes, a single injection of STZ (55 mg/kg, i.p.) was administered to the animals. Diabetic rats were treated with tropisetron (3 mg/kg) and glibenclamide (1 mg/kg) for 2 weeks. According to the conducted analysis, diabetes led to renal dysfunction (reduction in glomerular filtration rate and urine urea and creatinine as well as elevation in plasma urea and creatinine) and abnormalities in antioxidant defense system (reduction in TAC and elevation in MDA), compared with the control group, which was prevented by tropisetron treatment. Reverse transcription-quantitative polymerase chain reaction and western blotting analysis demonstrated that SIRT1 gene expression decreased while FOXO3a and NF-κB gene expression as well as phosphorylated FOXO3a/total FOXO3a protein ratios and claudin-1 protein level increased in the kidney of diabetic rats compared with the control group. Herein, the results of this research showed that tropisetron treatment reversed these changes. Besides, all these changes were comparable with those produced by glibenclamide as a positive control. Hence, tropisetron ameliorated renal damage due to diabetic nephropathy possibly by suppressing oxidative stress and alteration of SIRT1, FOXO3a, and claudin-1 levels.

Protective effect of metformin on rat diabetic retinopathy involves suppression of toll-like receptor 4/nuclear factor-k B expression and glutamate excitotoxicity

Microvascular complications of diabetes mellitus are progressively significant reasons for mortality. Metformin (MET) is considered as the first-line therapy for type 2 diabetes patients, and may be especially beneficial in cases of diabetic retinopathy although the precise mechanisms of MET action are not fully elucidated. The current study was designed to inspect the antioxidant and modulatory actions of MET on DRET in streptozotocin-induced diabetic rats. The effect of MET on the toll-like receptor 4/nuclear factor kappa B (TLR4/NFkB), inflammatory burden and glutamate excitotoxicity was assessed. Twenty-four male rats were assigned to four experimental groups: (1) Vehicle group, (2) Diabetic control: developed diabetes by injection of streptozotocin (60 mg/kg, i.p.). (3&4) Diabetic + MET group: diabetic rats were left for 9 weeks without treatment and then received oral MET 100 and 200 mg/kg for 6 weeks. Retinal samples were utilized in biochemical, histological, immunohistochemical and electron microscopic studies. MET administration significantly decreased retinal level of insulin growth factor and significantly suppressed the diabetic induced increase of malondialdehyde, glutamate, tumor necrosis factor-α and vascular endothelial growth factor (VEGF). Further, MET decreased the retinal mRNA expression of NFkB, tumor necrosis factor-α and TLR4 in diabetic rats. The current findings shed the light on MET's efficacy as an adjuvant therapy to hinder the development of diabetic retinopathy, at least partly, via inhibition of oxidative stress-induced NFkB/TLR4 pathway and suppression of glutamate excitotoxicity.

The interplay of the inhibitory effect of nifuroxazide on NF-κB/STAT3 signaling attenuates acetic acid-induced ulcerative colitis in rats

Ulcerative colitis (UC) is a disease of increased worldwide prevalence. UC progression is associated with serious complications that leave the patient with considerable health burdens. Nifuroxazide is an oral nitrofuran antibiotic used as antidiarrheal medication. The current study places an emphasis on investigating the potential therapeutic effectiveness of nifuroxazide (10 mg/kg) and (20 mg/kg) against acetic acid (AA)-induced UC. Intra-rectal AA induced a significant colonic injury and impairment of colonic biochemical and functional incidences. Nifuroxazide in a dose-dependent manner significantly corrected UC associated injury. Macroscopic scoring of UC, serum lactate dehydrogenase (LDH) activity, C-reactive protein (CRP) titer, colon malondialdehyde (MDA) and total nitric oxide (NOx) contents significantly declined. Meanwhile, serum total antioxidant capacity (TAC) and colon catalase, superoxide dismutase (SOD) and glutathione transferase (GST) activities and reduced glutathione (GSH) concentration significantly increased in a dose-dependent way. Ultimately, histopathological, immunohistochemical and ultramicroscopic analysis of colon specimen revealed significant improvement. To pinpoint the mechanistic pathway underlying the curative effect of nifuroxazide, colon expression of NF-κB, caspase-3 was evaluated along with STAT-3 activation. Nifuroxazide induced a dose-dependent significant suppression of NF-κB and caspase-3 signaling together with STAT3 signaling. In conclusion; nifuroxazide can be proposed as a therapeutic candidate to attenuate UC and its associated symptoms. The potential underlying mechanism involves suppression of NF-κB/STAT-3/caspase- signaling.

Protective effect of isoliquiritigenin on experimental diabetic nephropathy in rats: Impact on Sirt-1/NFκB balance and NLRP3 expression

The prevalence of diabetes mellitus (DM) drastically increases worldwide. Persistent hyperglycemia affects body microvasculature causing injuries to kidney producing diabetic nephropathy (DNE). Manifestation of these microvascular complications is associated with disturbed redox homeostasis. The current study evaluated the effect of isoliquiritigenin (ISLQ), a bioactive chalcone found in licorice which is known for its antioxidant effect, on diabetes-induced renal injury. DM was prompted in male rats by streptozotocin (STZ, 50 mg/kg, intraperitoneally). ISLQ was administrated by oral gavage for 8 weeks at a dose (20 mg/kg/day). Features of renal injury were observed in kidneys of diabetic rats including, albuminuria and deteriorated renal function. Renal dysfunction was associated with reduced sirtuin-1 (Sirt-1) expression, increased renal oxidative stress, nucleotide-binding domain and leucine-rich repeat containing protein-3 (NLRP3), nuclear factor-κB (NFκB) and inflammatory cytokines interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α). Moreover, there was significant downregulation of anti-inflammatory cytokine interleukin-10 (IL-10), glomerular and tubular injury and collagen accumulation. ISLQ administration preserved renal function and architecture, restored Sirt1 and renal oxidant-antioxidant balance, dampened inflammation and attenuated collagen accumulation. It can be inferred that ISLQ possess a protective effect and could have a potential as a food supplement to halt development and progression of DNE.

A novel role of nifuroxazide in attenuation of sepsis-associated acute lung and myocardial injuries; role of TLR4/NLPR3/IL-1β signaling interruption

Acute lung injury (ALI) and the subsequent multi-system organ failure is a serious health problem with devastating impacts on the health care systems. Indeed, the world has been facing an un-preceded situation in the past couple of months following COVID-19 infestation and the associated high-mortality rates mainly attributed to sepsis and the associated multiple organ failures of particular concern; acute respiratory distress syndrome post lung injury. The current study provides evidence on the ameliorative impact of nifuroxazide, and FDA approved antidiarrheal drug in attenuation of lipopolysaccharide (LPS)-induced ALI and myocarditis when administrated either in prophylactic or curative regimens. Nifuroxazide administration was associated with a significant improvement in lung and heart histopathological characteristics and architecture with retraction of LPS-induced inflammatory-infiltration. This was associated with retraction in serum biomarkers of cellular injury of which; LDH, CK-MB, and ALP. Nifuroxazide administration was associated with a significant improvement in both lung and heart oxidative status. Such positive outcomes were underlined by a significant inhibitory effect of nifuroxazide on lung and heart contents of toll-like receptor (4) (TLR4)/the inflammasome NALPR3/interleukin- 1β (IL-1β). In conclusion: Nifuroxazide attenuates LPS-induced ALI and myocardial injury via interruption of TLR4/NALPR3/IL-1β signaling. Thus it can offer a potential approach for attenuation of sepsis in critically ill patients.

Inhibitory effect of valproate sodium on pain behavior in diabetic mice involves suppression of spinal histone deacetylase 1 and inflammatory mediators

Anti-epileptic medications are included in the international guidelines for managing neuropathic pain. Valproate sodium (VPS) was recently described as "the forgotten analgesic" and has been reported to relief pain in various models of neuropathic pain. Some studies reported anti-inflammatory and histone deacetylase 1 (HDA1) inhibitory properties for sodium valproate. The aim of the current study was to investigate the modulatory effect of VPS on pain behavior and inflammatory reactions in alloxan-induced diabetic neuropathy focusing on HDA1 inhibition and glia reactivity. 28 Male Swiss albino mice were allocated into four groups, (1) vehicle group, (2) alloxan-diabetic group, (3 & 4) alloxan+VPS (25 or 50 mg/kg) groups. VPS was given daily for 5 weeks by oral gavage. Pain behavior demonstrated increased allodynia (von-Frey filaments) and hyperalgesia (hot-plate test) in alloxan-diabetic mice that was reduced significantly by at least one of VPS doses. Sciatic nerves in diabetic mice showed increased histopathology score, increased silver staining for the nerves-indicating myelopathy- and a decrease in immunostaining for nerve growth factor. Spinal cord of diabetic mice showed greater histopathologic score, increased CD11b and glia fibrillary acidic protein (GFAP) immunostaining than vehicle treated mice. Molecular investigations highlighted greater content of spinal histone deacetylases, tumor necrosis factor-α (TNF-α) and interlukin-1β (IL1β) that were favorably modified by VPS. Overall, the current data confirmed that the pain killing and anti-inflammatory activity of VPS is at least partly mediated through inhibition of spinal HDA1 and glia reactivity. These findings support the view of inviting antiepileptics for treating neuropathies.

Nifuroxazide ameliorates lipid and glucose metabolism in palmitate-induced HepG2 cells

Inflammation constitutes an important component of non-alcoholic fatty liver disease. STAT3 is a direct target of inflammatory cytokines, but also mediates glycolipid metabolism in the liver. As a potent inhibitor of STAT3, the effect of Nifuroxazide (Nifu) on glycolipid metabolism in liver has not been reported. In this study, we used palmitic acid (PA)-induced HepG2 cells to examine the expression of inflammatory factors and apoptosis-related proteins and the content of triglyceride (TG), total cholesterol (TC), and glycogen. The expression of hepatic lipogenic proteins (ACCα, SREBP-1c, FAS), gluconeogenesis enzymes (PEPCK, G6Pase, and IRS2), the IL-6/STAT3/SOCS3 inflammatory axis, and the insulin signaling pathway was determined. Our study shows that Nifu significantly improves lipid metabolism disorders in the PA-induced HepG2 cells, whereas, it remarkably reduced intracellular free fatty acid (FFA), TG, and TC content, suppressed lipid synthesis, and increased lipid decomposition. Our results also showed that Nifu significantly improved dysregulated glucose metabolism in the PA-treated HepG2 cells, increased glycogen content, and inhibited gluconeogenesis. Further research indicated that Nifu markedly inhibited activation of the IL-6/STAT3/SOCS3 signaling pathway. Finally, due to anti-inflammatory stress, Nifu enhanced insulin signaling in the PA-induced HepG2 cells. Therefore, Nifu can improve glucose and lipid metabolism in the PA-induced HepG2 cells, which provides new evidence that Nifu has a positive effect on PA-induced cellular hepatic steatosis and improves glucose metabolism in HepG2 cells, providing a new perspective for studying drug treatment of glucose and lipid metabolism disorders.

Inflammation constitutes an important component of non-alcoholic fatty liver disease.

The PKCβ-p66shc-NADPH oxidase pathway plays a crucial role in diabetic nephropathy

Objectives

Oxidative stress plays a critical role in the pathogenesis of diabetic nephropathy (DN). p66shc is closely related to oxidative stress. However, the exact mechanism of its involvement in diabetic nephropathy is poorly understood. This study aimed to investigate the role of the p66shc-related pathway in diabetic nephropathy.

Methods

In an in-vivo experiment, rats were injected with streptozotocin to induce early diabetic nephropathy. The treatment groups were an aminoguanidine group and an enzastaurin group. In an in-vitro experiment, human renal proximal tubule epithelial cells (HK-2 cells) were cultured and incubated with high glucose.

Key findings

Upregulated protein expression of p66shc and p-p66shc was found in vivo and in vitro when cells were stimulated by high levels of glucose; this effect was accompanied by enhanced oxidative stress and damaged renal function, both of which were alleviated by p66shc siRNA. p66shc regulated NADPH oxidase, further promoting activation of oxidative stress. As an inhibitor of PKCβ, enzastaurin reduced the abnormal expression of p66shc and NADPH oxidase and alleviated renal injury.

Conclusions

This study demonstrated enzastaurin alleviated diabetic renal injury via modulation of the PKCβ-p66shc-NADPH oxidase pathway, which provided a new perspective for the treatment of early DN.