Thymoquinone Ameliorates Renal Oxidative Damage and Proliferative Response Induced by Mercuric Chloride in Rats

Mirabegron, dependent on β3-adrenergic receptor, alleviates mercuric chloride-induced kidney injury by reversing the impact on the inflammatory network, M1/M2 macrophages, and claudin-2

The β3-adrenergic receptor (β3-AR) agonism mirabegron is used to treat overactive urinary bladder syndrome; however, its role against acute kidney injury (AKI) is not unveiled, hence, we aim to repurpose mirabegron in the treatment of mercuric chloride (HgCl2)-induced AKI. Rats were allocated into normal, normal + mirabegron, HgCl2 untreated, HgCl2 + mirabegron, and HgCl2 + the β3-AR blocker SR59230A + mirabegron. The latter increased the mRNA of β3-AR and miR-127 besides downregulating NF-κB p65 protein expression and the contents of its downstream targets iNOS, IL-4, -13, and -17 but increased that of IL-10 to attest its anti-inflammatory capacity. Besides, mirabegron downregulated the protein expression of STAT-6, PI3K, and ERK1/2, the downstream targets of the above cytokines. Additionally, it enhanced the transcription factor PPAR-α but turned off the harmful hub HNF-4α/HNF-1α and the lipid peroxide marker MDA. Mirabegron also downregulated the CD-163 protein expression, which besides the inhibited correlated cytokines of M1 (NF-κB p65, iNOS, IL-17) and M2 (IL-4, IL-13, CD163, STAT6, ERK1/2), inactivated the macrophage phenotypes. The crosstalk between these parameters was echoed in the maintenance of claudin-2, kidney function-related early (cystatin-C, KIM-1, NGAL), and late (creatinine, BUN) injury markers, besides recovering the microscopic structures. Nonetheless, the pre-administration of SR59230A has nullified the beneficial effects of mirabegron on the aforementioned parameters. Here we verified that mirabegron can berepurposedto treat HgCl2-induced AKI by activating the β3-AR. Mirabegron signified its effect by inhibiting inflammation, oxidative stress, and the activated M1/M2 macrophages, events that preserved the proximal tubular tight junction claudin-2 via the intersection of several trajectories.

Anandamide modulates WNT-5A/BCL-2, IP3/NFATc1, and HMGB1/NF-κB trajectories to protect against mercuric chloride-induced acute kidney injury

Endocannabinoid anandamide (AEA) has a physiological role in regulating renal blood flow, whereas its analogs ameliorated renal ischemia/reperfusion injury. Nonetheless, the role of AEA against mercuric chloride (HgCl₂)-induced renal toxicity has not been unraveled. Rats were allocated into control, HgCl₂, and HgCl₂/AEA treated groups. The administration of AEA quelled the HgCl₂-mediated increase in inositol trisphosphate (IP3) and nuclear factor of activated T-cells cytoplasmic 1 (NFATc1). The endocannabinoid also signified its anti-inflammatory potential by turning off the inflammatory cascade evidenced by the suppression of high mobility group box protein-1 (HMGB1), receptor of glycated end products (RAGE), nuclear factor-κB p65 (NF-κB), and unexpectedly PPAR-γ. Additionally, the aptitude of AEA to inhibit malondialdehyde and boost glutathione points to its antioxidant capacity. Moreover, AEA by enhancing the depleted renal WNT-5A and reducing cystatin-C and KIM-1 (two kidney function parameters) partly verified its anti-apoptotic capacity, confirmed by inhibiting caspase-3 and increasing B-cell lymphoma-2 (BCL-2). The beneficial effect of AEA was mirrored by the improved architecture and kidney function evidenced by the reduction in cystatin-C, KIM-1, creatinine, BUN, and caspase1-induced activated IL-18. In conclusion, our results verify the reno-protective potential of AEA against HgCl₂-induced kidney injury by its anti-inflammatory, antioxidant, and anti-apoptotic capacities by modulating WNT-5A/BCL-2, IP3/NFATC1, HMGB-1/RAGE/NF-κB, caspase-1/IL-18, and caspase-3/BCL-2 cues.

COVID-19 and Thymoquinone: Clinical Benefits, Cure, and Challenges

In today’s world, the outbreak of the coronavirus disease 2019 (COVID-19) has spread throughout the world, causing severe acute respiratory syndrome (SARS) and several associated complications in various organs (heart, liver, kidney, and gastrointestinal tract), as well as significant multiple organ dysfunction, shock, and even death. In order to overcome the serious complications associated with this pandemic virus and to prevent SARS-CoV-2 entry into the host cell, it is necessary to repurpose currently available drugs with a broad medicinal application as soon as they become available. There are several therapeutics under investigation for improving the overall prognosis of COVID-19 patients, but none of them has demonstrated clinical efficacy to date, which is disappointing. It is in this pattern that Nigella sativa seeds manifest their extensive therapeutic effects, which have been reported to be particularly effective in the treatment of skin diseases, jaundice, and gastrointestinal problems. One important component of these seeds is thymoquinone (TQ), which has a wide range of beneficial properties, including antioxidant and anti-inflammatory properties, as well as antibacterial and parasitic properties, in addition to anticarcinogenic, antiallergic, and antiviral properties. This comprehensive review discussed the possibility of an emerging natural drug with a wide range of medical applications; the use of TQ to overcome the complications of COVID-19 infection; and the challenges that are impeding the commercialization of this promising phytochemical compound. TQ is recommended as a highly effective weapon in the fight against the novel coronavirus because of its dual antiviral action, in addition to its capacity to lessen the possibility of SARS-CoV-2 penetration into cells. However, future clinical trials are required to confirm the role of TQ in overcoming the complications of COVID-19 infection.

Cross-Regulation between Autophagy and Apoptosis Induced by Vitamin E and Lactobacillus Plantarum through Beclin-1 Network

Autophagy and apoptosis are two important regulatory mechanisms for how the body can respond to diseases. This study was designed to investigate the protective actions of vitamin E (Vit-E) and lactobacillus plantarum (Lac-B) against mercuric chloride (HgCl₂)-induced kidney injury. Thirty albino rats were divided into five groups: group 1 served as the normal group; rats in group 2 received high doses of HgCl₂; rats in groups 3, 4 and 5 were given Vit-E, Lac-B and the combination of Vit-E and Lac-B, respectively along with HgCl₂ for two weeks. HgCl₂ provoked renal injury, manifested by elevation in serum urea, urea nitrogen and creatinine. Kidney levels of oxidative stress and inflammation were markedly increased post HgCl₂ administration. Moreover, HgCl₂ significantly elevated the gene expression levels of VCAM-1 and cystatin C, while podocin was downregulated. Additionally, it markedly decreased the protein expression of Beclin-1 and Bcl-2. Histopathological examination revealed massive degeneration with congested blood vessels following HgCl₂ administration. Treatment with Vit-E or/and Lac-B restored the normal levels of the previously mentioned parameters, as well as improved the morphology of kidney tissues. Both Vit-E and Lac-B provided a protective effect against HgCl₂-induced kidney damage by regulating autophagy and apoptosis.

Bax/Bcl-2 Cascade Is Regulated by the EGFR Pathway: Therapeutic Targeting of Non-Small Cell Lung Cancer

Non-small cell lung carcinoma (NSCLC) comprises 80%-85% of lung cancer cases. EGFR is involved in several cancer developments, including NSCLC. The EGFR pathway regulates the Bax/Bcl-2 cascade in NSCLC. Increasing understanding of the molecular mechanisms of fundamental tumor progression has guided the development of numerous antitumor drugs. The development and improvement of rationally planned inhibitors and agents targeting particular cellular and biological pathways in cancer have been signified as a most important paradigm shift in the strategy to treat and manage lung cancer. Newer approaches and novel chemotherapeutic agents are required to accompany present cancer therapies for improving efficiency. Using natural products as a drug with an effective delivery system may benefit therapeutics. Naturally originated compounds such as phytochemicals provide crucial sources for novel agents/drugs and resources for tumor therapy. Applying the small-molecule inhibitors (SMIs)/phytochemicals has led to potent preclinical discoveries in various human tumor preclinical models, including lung cancer. In this review, we summarize recent information on the molecular mechanisms of the Bax/Bcl-2 cascade and EGFR pathway in NSCLC and target them for therapeutic implications. We further described the therapeutic potential of Bax/Bcl-2/EGFR SMIs, mainly those with more potent and selectivity, including gefitinib, EGCG, ABT-737, thymoquinone, quercetin, and venetoclax. In addition, we explained the targeting EGFR pathway and ongoing in vitro and in vivo and clinical investigations in NSCLC. Exploration of such inhibitors facilitates the future treatment and management of NSCLC.

Thymoquinone Induces Nrf2 Mediated Adaptive Homeostasis: Implication for Mercuric Chloride-Induced Nephrotoxicity

BACKGROUND

the primary function of the kidney is to eliminate metabolic waste products and xenobiotics from the circulation. During this process, the kidney may become vulnerable to toxicity.

OBJECTIVE

it was aimed to investigate the impact of thymoquinone (TQ) in mercuric chloride (HgCl2)-induced nephrotoxicity through estimation of various proteins involved in natural defense mechanisms.

MATERIAL AND METHODS

HgCl2 (0.4 mg/kg) was administered to all groups (n = 5) except for the normal control. Three treatment groups received TQ (5, 10, and 15 mg/kg) 60 min before HgCl2 administration. The protective effect of TQ was evaluated from renal and liver function biomarkers, urine examination, glomerulus filtration rate (GFR), histopathological features, oxidative stress biomarkers, Hsp-70, apoptosis biomarkers, and gene expression.

RESULTS

TQ significantly attenuated hazardous effects of HgCl2 on renal and hepatic tissues. Urine albumin and glucose were considerably low in the treated groups in comparison with the HgCl2 group. TQ treatment also enhanced % GFR in rats. TQ-enhanced superoxide dismutase, catalase, and glutathione levels by enhancing the expression level of nuclear factor erythroid 2-related factor 2 (Nrf2). TQ increased Hsp-70 and Bcl-2 levels and reduced caspase-3 activity. TQ also protected cells against HgCl2-induced cell death and decreased % DNA fragmentation. TQ increased the expression of protective proteins metallothionein I and II and reduced the expression of kidney injury molecule-1 (Kim-1).

CONCLUSION

TQ showed protective effects against HgCl2-induced nephrotoxicity through modifications of various constitutive and inducible protein and enzyme levels in renal tissues.

The Antioxidant Efficacy of Wheatgrass (Triticum Aestivum) on Mercuric Chloride (HgCl2) - Induced Oxidative Stress in Rat Model

Mercury is a harmful toxic pollutant, which has hepato-nephrotoxic, hematotoxic, genotoxic and neurotoxic, effects. The aim of the study was to evaluate the protective efficacy of wheatgrass on mercuric chloride (HgCl2) induced oxidative stress and associated complications in rat model. Albino rats were divided into four groups (three rats per group). Group I normal control group. Group II oxidative stressed group received mercuric chloride (0.5 mg/kg/day). Group III only received wheatgrass extract (100 mg/kg/day), whereas Group IV received wheatgrass (100 mg/kg/day) after one hour, followed by mercuric chloride (0.5 mg/kg/day) for 30 days. The results of the study showed that wheatgrass supplementation significantly decreased the HgCl2 induced elevated oxidative stress parameters Plasma Malondialdehyde (MDA) content, Plasma membrane redox system (PMRS), Advanced oxidation protein products (AOPP), simultaneously elevated lipid profile (Total Cholesterol, Triglycerides, Low-density lipoprotein (LDL), liver enzymes as, Plasma Alkaline phosphatase (ALP), Aspartate aminotransferase (AST), and Alanine aminotransferase (ALT), Serum Urea, and Creatinine levels in rats. In addition, wheatgrass treatment improved the antioxidant status in terms of intracellular Reduced Glutathione (GSH), Ferric reducing antioxidant power (FRAP) and 2, 2- diphenyl -1- picrylhydrazyl (DPPH). Therefore it can be concluded that wheatgrass has great potential to diminish the stress-mediated complications and improve the antioxidant status.

Therapeutic impact of thymoquninone to alleviate ischemic brain injury via Nrf2/HO-1 pathway

Introduction: Reactive oxygen species (ROS)-mediated inflammation plays a crucial role in ischemic brain injury. Therefore, the activation of the nuclear erythroid 2 related protein and heme-oxygenase-1 (Nrf2/HO-1) pathway by thymoquinone (TQ) could ameliorate ischemic brain damage.Areas covered: The photo-thrombotic method was employed to assess the impact of TQ in attenuating ischemic brain damage in C57BL/6 J mice and thy1-YFP-16 transgenic mice. In vitro study of TQ efficiency to attenuate the oxygen-glucose deprivation/reoxygenation (OGD/R) induced cell death by fluorescence-activated cell sorting (FACs) analysis was also analyzed. The protein expression levels of Nrf2/HO-1, inflammatory, and apoptotic were evaluated by immunofluorescence and western blot techniques. Besides, mRNA expression level of inducible nitric oxide synthase (iNOS), proto-oncogene (c-MYC), proto-oncogene (c-FOS), 5-hydroxytryptamine receptors (5-HT), and autophagy-related 5 (Atg5) were evaluated by RT-qPCR. The dendritic spine density of YFP slices was determined by confocal microscope.Results: Our in vivo and in vitro results indicated that TQ significantly mitigates brain damage and motor dysfunction after ischemic stroke. These observations coincided with curtailed cell death, inflammation, oxidative stress, apoptosis, and autophagy. Most importantly, Nrf2/HO-1 signaling pathway activation by TQ was vital in the modulation of the above processes. Lastly, we found TQ to have minimal toxicity in liver tissue.Conclusion: Our study gives credence to TQ as a promising intervention therapy for cerebral ischemia that decreases inflammation, oxidative stress, and neuronal cell death via the Nrf2/HO-1 pathway, along with modulation of apoptotic and autophagic processes.

Protective roles of thymoquinone and vildagliptin in manganese-induced nephrotoxicity in adult albino rats

Despite being important in the body's mechanisms, excessive accumulation of manganese (Mn) can induce severe toxicity in vital organs of the body. Thymoquinone (TQ) is extracted from Nigella sativa seeds which recently gained popularity as dietary supplements and plant-based antioxidants. Vildagliptin (VLD) is a dipeptidyl peptidase IV (DPPIV) inhibitor, approved as anti-hyperglycemic agents with cardioprotective and renoprotective effects. The present study aimed to investigate the nephrotoxicity of Mn and the potential protective effects of thymoquinone and vildagliptin. Sixty-four adult male albino rats were equally divided into 8 groups: group I (control, received no medication), group II (vehicle, received normal saline), group III (TQ, 50 mg/kg/day), group IV (VLD, 10 mg/kg/day), group V (MnCl₂, 50 mg/kg/day), group VI (Mn+TQ), group VII (Mn+VLD), and group VIII (Mn+TQ+VLD). Groups VI, VII, and VIII, received the same previously mentioned doses. All drugs were orally gavaged for 12 weeks. Manganese administration resulted in an elevation in the levels of serum and tissues Mn, blood glucose, serum urea, creatinine, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and reduction in insulin, kidney superoxide dismutase (SOD), glutathione (GSH), and interleukin-10. Histopathological structural renal damage was detected associated with strong positive immunoexpression of caspase-3. On the other hand, individual or combined TQ and VLD administration with Mn significantly decreased the serum and tissue levels of Mn, declined the blood glucose, inflammatory markers, oxidative stress markers, ameliorated the histopathological effects, and down-regulated the immunoexpression of caspase-3. In conclusion, TQ and VLD co-administration elicited protective effects against Mn-induced nephrotoxicity.

Thymoquinone and fluoxetine alleviate depression via attenuating oxidative damage and inflammatory markers in type-2 diabetic rats

The study was designed to find out the effect of thymoquinone (TQ) alone and combination of TQ + fluoxetine in depression of type-2 diabetic rats. Glucose level was significantly decreased in TQ alone treated group, whereas no significant change was recorded when TQ was combined with fluoxetine. Administration of TQ alone and combination of TQ and fluoxetine significantly decreased immobility time, increased latency to immobility and increased locomotor activity. Treatment with TQ alone significantly decreased level of TBARS, increased GSH and restored the activities of antioxidant enzymes (GPx, GR & CAT). However, TQ and fluoxetine combination reduced TBARS level, increased GSH content but no change in the antioxidant enzymes activities. Inflammatory markers (IL-1β, IL-6 & TNF-α) levels were significantly reduced after the administration of TQ alone and TQ + fluoxetine. The study suggests that combination of TQ and fluoxetine can be used to control depression in type-2 diabetes mellitus.

Nigella sativaand its Derivatives as Food Toxicity Protectant Agents

Exposure to food toxins generate multiple adverse health effects. Heavy metals, antibiotics residue, mycotoxins, pesticides and some food additives are examples of the most important food toxins. The common mechanism of toxicity and carcinogenicity effects of food toxins is the generation of oxidative stress that leads to DNA damages. Moreover, based on epidemiologic evidence unhealthy eating habits and food toxicities are associated with cancers occurrence. Therefore, application of bioactive food additives as harmless or safe components in food industry is expensive. Nigella sativa L. is a broadly used herb-drug for various diseases all over the world and has been used as preservative and food additive. Based on various studies N. sativa has shown various pharmacological activities including therapeutic efficacy against different human diseases and antioxidant anti-inflammatory effects against environmental toxins. N. sativa decreases the adverse health effects induced by mentioned food toxins via modulating the action of antioxidant enzymes such as glutathione peroxidase (GPx), glutathione-S-transferase catalase and act as reactive oxygen species (ROS) scavengers in different organs. Besides, N. sativa and thymoquinone (TQ) have protective effects on food products through removal and inhibition of various toxic compounds. Therefore, in the present review we will describe all protective effects of N. sativa and its main constituents, TQ, against food induced toxicities.

Thymoquinone and diallyl sulfide protect against fipronil-induced oxidative injury in rats

Fipronil (FPN) is a phenylpyrazole insecticide, widely used for agricultural and veterinary activities. Early reports indicated that FIP organ toxicity is primarily mediated by the induction of oxidative stress. Both thymoquinone (TQ) and diallyl sulfide (DAS) are natural antioxidants with established health benefits. This study investigated the potential ameliorative effects of DAS and TQ against FPN-induced toxicity in rats. Thirty-two male Wistar rats (150-180 g) were randomized into four treatment groups, receiving (I) saline, (II) FPN (10 mg/kg bw), (III) FPN with DAS (200 mg/kg bw), and (IV) FPN with TQ (10 mg/kg bw). All treatments were administered once daily for 28 days. The results showed that compared to the control rats, FPN-treated rats had significantly increased (p < 0.05) serum levels of uric acid, urea, creatinine, cholesterol, aspartate transferase, alanine transferase, alkaline phosphatase, lactate dehydrogenase, and γ-glutamyl transferase. Moreover, FPN significantly reduced (p < 0.05) the serum levels of total proteins, albumin, and triglycerides. In addition, compared with the control group, FPN-treated rats had significantly elevated (p < 0.05) malondialdehyde and nitric oxide levels, as well as significantly reduced glutathione concentration and activities of glutathione peroxidase, superoxide dismutase, and catalase enzymes in the hepatic, renal, and brain tissues. Cotreatment with DAS or TQ significantly ameliorated (p < 0.05) the FPN-induced alterations in all the previously mentioned parameters with more frequent restoration of normal control ranges in the TQ group. In conclusion, both DAS and TQ alleviated the oxidative injury of FPN, probably by enhancing tissue antioxidant defenses.

An Overview on Renoprotective Effects of Thymoquinone

Background

Kidneys as vital organs remove waste material from blood. Additionally, they may also have a role in the electrolyte balance, regulation of blood pressure, and red blood cell genesis. Kidney diseases may be caused by several factors such as ischemia/reperfusion injury, diabetes, and nephrotoxic agents. Oxidative stress and inflammation are involved in the pathogenesis and progression of kidney diseases. Traditionally, natural antioxidants are used for treatment of renal failure in various countries.

Summary

People usually select natural antioxidants since they have an opinion that herbal medicine has not any important side effects. Nigella sativa is a flavoring herb that is widely used as a condiment and as a remedy for many disorders. Thymoquinone (TQ), the most important component of black seeds, mainly oil, is considered as an active agent responsible for a lot of the seed's useful effects. This review describes the protective roles and related mechanisms of TQ against renal disorders. The search terms, including TQ, antioxidant, renal ischemia-reperfusion, diabetic nephropathy, and nephrotoxic agent were searched in scientific databases. TQ showed anti-inflammatory and antioxidant properties in animal and in vitro models of several renal diseases caused by inflammation and oxidative stress.

Key Messages

Experimental studies have shown beneficial effects of TQ against renal diseases; however, well-designed clinical trials in humans are required to confirm these effects.

Therapeutic Potential and Pharmaceutical Development of Thymoquinone: A Multitargeted Molecule of Natural Origin

Thymoquinone, a monoterpene molecule is chemically known as 2-methyl-5-isopropyl-1, 4-benzoquinone. It is abundantly present in seeds of Nigella sativa L. that is popularly known as black cumin or black seed and belongs to the family Ranunculaceae. A large number of studies have revealed that thymoquinone is the major active constituent in N. sativa oil this constituent is responsible for the majority of the pharmacological properties. The beneficial organoprotective activities of thymoquinone in experimental animal models of different human diseases are attributed to the potent anti-oxidant and anti-inflammatory properties. Thymoquinone has also been shown to alter numerous molecular and signaling pathways in many inflammatory and degenerative diseases including cancer. Thymoquinone has been reported to possess potent lipophilicity and limited bioavailability and exhibits light and heat sensitivity. Altogether, these physiochemical properties encumber the successful formulation for the delivery of drug in oral dosages form and restrict the pharmaceutical development. In recent past, many efforts were undertaken to improve the bioavailability for clinical usage by manipulating the physiochemical parameters. The present review aimed to provide insights regarding the physicochemical characteristics, pharmacokinetics and the methods to promote pharmaceutical development and endorse the clinical usage of TQ in future by overcoming the associated physiochemical obstacles. It also enumerates briefly the pharmacological and molecular targets of thymoquinone as well as the pharmacological properties in various diseases and the underlying molecular mechanism. Though, a convincing number of experimental studies are available but human studies are not available with thymoquinone despite of the long history of use of black cumin in different diseases. Thus, the clinical studies including pharmacokinetic studies and regulatory toxicity studies are required to encourage the clinical development of thymoquinone.

Oral administration of thymoquinone mitigates the effect of cisplatin on brush border membrane enzymes, energy metabolism and antioxidant system in rat intestine

Cisplatin (CP) is a widely used chemotherapeutic agent that elicits severe gastrointestinal toxicity. Nigella sativa, a member of family Ranunculaceae, is one of the most revered medicinal plant known for its numerous health benefits. Thymoquinone (TQ), a major bioactive component derived from the volatile oil of Nigella sativa seeds, has been shown to improve gastrointestinal functions in animal models of acute gastric/intestinal injury. In view of this, the aim of the present study was to investigate the protective effect of TQ on CP induced toxicity in rat intestine and to elucidate the mechanism underlying these effects. Rats were divided into four groups viz. control, CP, TQ and CP+TQ. Animals in CP+TQ and TQ groups were orally administered TQ (1.5mg/kg bwt) with and without a single intraperitoneal dose of CP (6mg/kg bwt) respectively. The effect of TQ was determined on CP induced alterations in the activities of brush border membrane (BBM), carbohydrate metabolism, and antioxidant defense enzymes in rat intestine. TQ administration significantly mitigated CP induced decline in the specific activities of BBM marker enzymes, both in the mucosal homogenates and in the BBM vesicles (BBMV) prepared from intestinal mucosa. Furthermore, TQ administration restored the redox and metabolic status of intestinal mucosal tissue in CP treated rats. The biochemical results were supported by histopathological findings that showed extensive damage to intestine in CP treated rats and markedly preserved intestinal histoarchitecture in CP and TQ co-treated group. The biochemical and histological data suggest a protective effect of TQ against CP-induced gastrointestinal damage. Thus, TQ may have a potential for clinical application to counteract the accompanying gastrointestinal toxicity in CP chemotherapy.

Nigella sativa Relieves the Altered Insulin Receptor Signaling in Streptozotocin-Induced Diabetic Rats Fed with a High-Fat Diet

The black cumin (Nigella sativa) "NS" or the black seeds have many pharmacological activities such as antioxidant, anticarcinogenic, antihypertensive, and antidiabetic properties. In this work, streptozotocin-induced diabetic rats fed with a high-fat diet were treated daily with NS oil (NSO) in order to study the effect on the blood glucose, lipid profile, oxidative stress parameters, and the gene expression of some insulin receptor-induced signaling molecules. This treatment was combined also with some drugs (metformin and glimepiride) and the insulin receptor inhibitor I-OMe-AG538. The administration of NSO significantly induced the gene expression of insulin receptor compared to rats that did not receive NSO. Also, it upregulated the expression of insulin-like growth factor-1 and phosphoinositide-3 kinase, whereas the expression of ADAM-17 was downregulated. The expression of ADAM-17 is corroborated by the analysis of TIMP-3 content. In addition, the NSO significantly reduced blood glucose level, components of the lipid profile, oxidative stress parameters, serum insulin/insulin receptor ratio, and the tumor necrosis factor-α, confirming that NSO has an antidiabetic activity. Thus, the daily NSO treatment in our rat model indicates that NSO has a potential in the management of diabetes as well as improvement of insulin-induced signaling.

Protective Effects of Thymoquinone against Methotrexate-Induced Germ Cell Apoptosis in Male Mice

Background

Toxic effects of anti-cancer and other drugs on the normal tissues could be reduced by the herbal plants and their fractions. This study investigated the protective effect of thymoquinone (TQ) as a fraction of Nigella sativa on methotrexate (MTX)- induced germ cell apoptosis in male mice.

Materials and Methods

In this experimental study, thirty male Balb/c mice were divided randomly into 5 groups (n=6). A single dose of MTX (20 mg/kg) and different concentrations of TQ were administrated for 4 consecutive days. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay was performed on paraffin embedded tissue sections to analysis the occurrence of apoptosis in the testis. Reverse transcription polymerase chain reaction (RT-PCR) of apoptosis-related genes was performed with RNA extracted from testes of the mice. Statistical analysis was done using one-way ANOVA.

Results

In the MTX group, there was a significant increase in morphologic sign of germ cell degeneration of tubules (48 ± 0.6%), apoptotic index (AI; 2.3 ± 0.6%), as well as mRNA expression of p53 (P=0.008), caspase 8 (P=0.002), caspase 3 (P=0.005), caspase 9 (P=0.000), bax (P=0.004) and the ratio of bax/bcl-2 (P=0.000), whereas there was an decrease in the expression of bcl-2 (P=0.003), as compared to control group. In MTX+TQ groups, the data showed that different concentrations of TQ could improve the harmful effects caused by the MTX. The best protective effects were achieved in MTX+TQ (10 mg/kg).

Conclusion

TQ protects testicular germ cell against MTX-induced apoptosis by affecting related genes regulation.

Neuroprotective Effects of Thymoquinone on the Hippocampus in a Rat Model of Traumatic Brain Injury

BACKGROUND

Traumatic brain injury is a leading cause of morbidity and mortality worldwide. We evaluated the neuroprotective effects of thymoquinone (TQ) in a rat model of traumatic brain injury by using biochemical and histopathologic methods for the first time.

MATERIALS AND METHODS

Twenty-four rats were divided into sham (n = 8), trauma (n = 8), and TQ-treated (n = 8) groups. A moderate degree of head trauma was induced with the use of Feeney's falling weight technique, and TQ (5 mg/kg/day) was administered to the TQ-treated group for 7 days. All animals were killed after cardiac perfusion. Brain tissues were extracted immediately after perfusion without damaging the tissues. Biochemical procedures were performed with the serum, and a histopathologic evaluation was performed on the brain tissues. Biochemical experiments included malondialdehyde (MDA), reduced and oxidized coenzyme Q10 analysis, DNA isolation and hydroylazation, and glutathione peroxidase, and superoxide dismutase analyses.

RESULTS

Neuron density in contralateral hippocampal regions (CA1, CA2-3, and CA4) 7 days after the trauma decreased significantly in the trauma and TQ-treated groups, compared with that in the control group. Neuron densities in contralateral hippocampal regions (CA1, CA2-3, and CA4) were greater in the TQ-treated group than in the trauma group. TQ did not increase superoxide dismutase or glutathione peroxidase antioxidant levels. However, TQ decreased the MDA levels.

CONCLUSIONS

These results indicate that TQ has a healing effect on neural cells after head injury and this effect is mediated by decreasing MDA levels in the nuclei and mitochondrial membrane of neurons.

Thymoquinone protects end organs from abdominal aorta ischemia/reperfusion injury in a rat model

Introduction

Previous studies have demonstrated that thymoquinone has protective effects against ischemia reperfusion injury to various organs like lungs, kidneys and liver in different experimental models.

Objective

We aimed to determine whether thymoquinone has favorable effects on lung, renal, heart tissues and oxidative stress in abdominal aorta ischemia-reperfusion injury.

Methods

Thirty rats were divided into three groups as sham (n=10), control (n=10) and thymoquinone (TQ) treatment group (n=10). Control and TQ-treatment groups underwent abdominal aorta ischemia for 45 minutes followed by a 120-min period of reperfusion. In the TQ-treatment group, thymoquinone was given 5 minutes. before reperfusion at a dose of 20 mg/kg via an intraperitoneal route. Total antioxidant capacity, total oxidative status (TOS), and oxidative stress index (OSI) in blood serum were measured and lung, kidney, and heart tissue histopathology were evaluated with light microscopy.

Results

Total oxidative status and oxidative stress index activity in blood samples were statistically higher in the control group compared to the sham and TQ-treatment groups (P<0.001 for TOS and OSI). Control group injury scores were statistically higher compared to sham and TQ-treatment groups (P<0.001 for all comparisons).

Conclusion

Thymoquinone administered intraperitoneally was effective in reducing oxidative stress and histopathologic injury in an acute abdominal aorta ischemia-reperfusion rat model.

Cinnabar-induced subchronic renal injury is associated with increased apoptosis in rats

The aim of this study was to explore the role of apoptosis in cinnabar-induced renal injury in rats. To test this role, rats were dosed orally with cinnabar (1 g/kg/day) for 8 weeks or 12 weeks, and the control rats were treated with 5% carboxymethylcellulose solution. Levels of urinary mercury (UHg), renal mercury (RHg), serum creatinine (SCr), and urine kidney injury molecule 1 (KIM-1) were assessed, and renal pathology was analyzed. Apoptotic cells were identified and the apoptotic index was calculated. A rat antibody array was used to analyze expression of cytokines associated with apoptosis. Results from these analyses showed that UHg, RHg, and urine KIM-1, but not SCr, levels were significantly increased in cinnabar-treated rats. Renal pathological changes in cinnabar-treated rats included vacuolization of tubular cells, formation of protein casts, infiltration of inflammatory cells, and increase in the number of apoptotic tubular cells. In comparison to the control group, expression of FasL, Fas, TNF-α, TRAIL, activin A, and adiponectin was upregulated in the cinnabar-treated group. Collectively, our results suggest that prolonged use of cinnabar results in kidney damage due to accumulation of mercury and that the underlying mechanism involves apoptosis of tubular cells via a death receptor-mediated pathway.

Protective effects of thymoquinone and l-cysteine on cadmium-induced reproductive toxicity in rats

This study was conducted to investigate the possible protective role of thymoquinone (TQ) and l-cysteine on the reproductive toxicity of male rats induced by cadmium chloride (CdCl₂). Forty rats were divided into four even groups. The first group served as untreated control. The second, third and fourth groups received CdCl₂, CdCl₂ and TQ, and CdCl₂ and l-cysteine, respectively for 56 days. Cd exposure caused spermatological damage (decrease sperm count and motility and increased the rates of sperm abnormalities), decrease serum testosterone level and increased oxidative stress. Histological alterations were also observed in the form of vascular and cellular changes in CdCl₂ treated rats. The vascular changes were congestion of the blood vessels with interstitial edema in the testes, epididymis, seminal vesicle and prostate. The cellular changes were in the form of degenerative changes with presence of multinucleated giant cells in the lumen of seminiferous tubules, vacuolation and sloughing of the lining epithelium of the epididymis, seminal vesiculitis and prostatitis. Co-administration of TQ and l-cysteine with CdCl₂ increased glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) and testosterone and reduced lipid peroxidation (LPO) activity. In conclusion, our results showed that TQ and l-cysteine can ameliorate the deleterious effects of CdCl₂ probably by activating testicular endocrine and antioxidant systems.

Therapeutic Implications of Black Seed and Its Constituent Thymoquinone in the Prevention of Cancer through Inactivation and Activation of Molecular Pathways

The cancer is probably the most dreaded disease in both men and women and also major health problem worldwide. Despite its high prevalence, the exact molecular mechanisms of the development and progression are not fully understood. The current chemotherapy/radiotherapy regime used to treat cancer shows adverse side effect and may alter gene functions. Natural products are generally safe, effective, and less expensive substitutes of anticancer chemotherapeutics. Based on previous studies of their potential therapeutic uses, Nigella sativa and its constituents may be proved as good therapeutic options in the prevention of cancer. Black seeds are used as staple food in the Middle Eastern Countries for thousands of years and also in the treatment of diseases. Earlier studies have shown that N. sativa and its constituent thymoquinone (TQ) have important roles in the prevention and treatment of cancer by modulating cell signaling pathways. In this review, we summarize the role of N. sativa and its constituents TQ in the prevention of cancer through the activation or inactivation of molecular cell signaling pathways.

Effect of Thymoquinone on Oxidative Stress in Escherichia coli-Induced Pyelonephritis in Rats

BACKGROUND

Recurrent urinary tract infections are important in children and adults with diabetes mellitus and/or incontinence due to risk of pyelonephritis (PYN) and renal damage. There is a positive correlation released free radicals during PYN and renal damage. Experimental studies showed that antioxidant agents improve renal damage when used immediately after bacterial inoculation.

OBJECTIVE

The aim of the present study was to evaluate whether treatment by thymoquinone (TQ) before or during Escherichia coli inoculation prevents oxidative damage in acute pyelonephritis (PYN) in an ascending obstructive rat model.

METHODS

In this study, 42 Wistar rats were grouped as follows: control, PYN (24, 48, and 72 hours), and TQ-PYN (24, 48, and 72 hours). E. coli (1 ×10(9) colony forming units) was inoculated into the bladder via urethral catheterization in both the PYN and TQ groups. TQ injections were performed 24 hours before bacteria inoculation and repeated at 24-hour intervals during the indicated time at a dose of 10 mg/kg body weight intraperitoneally in TQ groups.

RESULTS

Superoxide dismutase activity was statistically lower in the TQ-PYN-48 and -72 groups than the PYN-48 and -72 groups (P < 0.001, P = 0.004, respectively). Catalase activity was significantly higher in PYN-24, -48, and -72 groups than the control group (P < 0.001). In addition, there was a significant difference between the TQ-PYN-24, -48, and -72 groups and PYN groups in terms of glutathione peroxidase activity (P < 0.001, P = 0.026, P = 0.046, respectively). When the TQ-PYN-72 group was compared with the PYN-72 group, malondialdehyde levels were significantly lower in the TQ-PYN-72 group than in the PYN-72 group (P = 0.033). A histologic examination also confirmed the protective effect of TQ. In statistical analysis of histopathologic findings, there were significant differences between the PYN-24 and TQ-PYN-24, PYN-48 and TQ-PYN-48, and PYN-72 and TQ-PYN-72 groups (P = 0.008, P < 0.001, P < 0.001, respectively).

CONCLUSIONS

The results indicate that TQ administration attenuated the oxidative damage that occurred in PYN and, therefore, could be used as a supportive agent to protect the kidneys from oxidative damage caused by PYN.

Protective effect of thymoquinone on glucose or methylglyoxal-induced glycation of superoxide dismutase

Glycation plays an important role in various oxidative stress related diseases. Superoxide dismutase (SOD) constitutes an essential defense against oxidative stress. The damage caused by oxidative stress is exacerbated if the antioxidant enzymes themselves are inactivated by glycation. Thymoquinone (TQ) has been reported to have various pharmacological activities. Therefore, the glycation of SOD by glucose or methylglyoxal (MG) and its protection by TQ has been investigated. Incubation of SOD with glucose, MG or both at 37 °C resulted in a progressive decrease in the activity of the enzyme, and a parallel decrease in the amount of protein on SDS-PAGE gels for glucose incubated SOD and formation of high molecular weight aggregates for MG or both glucose and MG incubated enzyme. TQ offered protection against glucose or MG induced loss in SOD activity and fragmentation/cross-linking. The antiglycating activity of TQ appears to be better for mild glycating agents. It is also effective in protecting against strong glycating agents, more when the exposure time to the glycating agent is short. TQ has also earlier been reported to have anti-diabetic effects, and this along with the observed antiglycating effect makes it an effective compound against diabetes and its complications.

Thymoquinone: fifty years of success in the battle against cancer models

Thymoquinone (TQ), the main active constituent of black seed essential oil, exhibits promising effects against inflammatory diseases and cancer. TQ, modulates signaling pathways that are key to cancer progression, and enhances the anticancer potential of clinical drugs while reducing their toxic side effects. Considering that TQ was isolated 50 years ago, this review focuses on TQ's chemical and pharmacological properties and the latest advances in TQ analog design and nanoformulation. We discuss our current state of knowledge of TQ's adjuvant potential and in vivo antitumor activity and highlight its ability to modulate the hallmarks of cancer.

Thymoquinone ameliorates lead-induced brain damage in Sprague Dawley rats

The present study aims to investigate the protective effects of thymoquinone, the major active ingredient of Nigella sativa seeds, against lead-induced brain damage in Sprague-Dawley rats. In which, 40 rats were divided into four groups (10 rats each). The first group served as control. The second, third and fourth groups received lead acetate, lead acetate and thymoquinone, and thymoquinone only, respectively, for one month. Lead acetate was given in drinking water at a concentration of 0.5 g/l (500 ppm). Thymoquinone was given daily at a dose of 20mg/kg b.w. in corn oil by gastric tube. Control and thymoquinone-treated rats showed normal brain histology. Treatment of rats with lead acetate was shown to produce degeneration of endothelial lining of brain blood vessels with peri-vascular cuffing of mononuclear cells consistent to lymphocytes, congestion of choroid plexus blood vessels, ischemic brain infarction, chromatolysis and neuronal degeneration, microglial reaction and neuronophagia, degeneration of hippocampal and cerebellar neurons, and axonal demyelination. On the other hand, co-administration of thymoquinone with lead acetate markedly decreased the incidence of lead acetate-induced pathological lesions. Thus the current study shed some light on the beneficial effects of thymoquinone against neurotoxic effects of lead in rats.

Mercury induces proliferation and reduces cell size in vascular smooth muscle cells through MAPK, oxidative stress and cyclooxygenase-2 pathways

Mercury exposure is known to increase cardiovascular risk but the underlying cellular mechanisms remain undetermined. We analyzed whether chronic exposure to HgCl2 affects vascular structure and the functional properties of vascular smooth muscle cells (VSMC) through oxidative stress/cyclooxygenase-2 dependent pathways. Mesenteric resistance arteries and aortas from Wistar rats treated with HgCl2 (first dose 4.6mgkg(-1), subsequent doses 0.07mgkg(-1)day(-1), 30days) and cultured aortic VSMC stimulated with HgCl2 (0.05-5μg/ml) were used. Treatment of rats with HgCl2 decreased wall thickness of the resistance and conductance vasculature, increased the number of SMC within the media and decreased SMC nucleus size. In VSMCs, exposure to HgCl2: 1) induced a proliferative response and a reduction in cell size; 2) increased superoxide anion production, NADPH oxidase activity, gene and/or protein levels of the NADPH oxidase subunit NOX-1, the EC- and Mn-superoxide dismutases and cyclooxygenase-2 (COX-2); 3) induced activation of ERK1/2 and p38 MAPK. Both antioxidants and COX-2 inhibitors normalized the proliferative response and the altered cell size induced by HgCl2. Blockade of ERK1/2 and p38 signaling pathways abolished the HgCl2-induced Nox1 and COX-2 expression and normalized the alterations induced by mercury in cell proliferation and size. In conclusion, long exposure of VSMC to low doses of mercury activates MAPK signaling pathways that result in activation of inflammatory proteins such as NADPH oxidase and COX-2 that in turn induce proliferation of VSMC and changes in cell size. These findings offer further evidence that mercury might be considered an environmental risk factor for cardiovascular disease.

Attenuation of oxidative stress-induced vascular endothelial dysfunction by thymoquinone

This study aimed to assess the effects of thymoquinone (TQ) on pyrogallol-induced endothelial dysfunction in isolated rabbit aorta. The protective effects of TQ were examined by incubating aortic rings in TQ concomitant with pyrogallol. The results revealed that pyrogallol produced significant enhancement of phenylephrine-induced contraction and impairment of acetylcholine-induced relaxation. Pyrogallol caused a significant increase in lipid peroxidation and reduction in the level of superoxide dismutase and reduced glutathione in the aortic homogenates. In addition, pyrogallol produced a significant decrease in nitrite/nitrate concentrations (NOx), constitutive nitric oxide synthase (cNOS) activity and an increase in inducible nitric oxide synthase (iNOS) activity in the aortic homogenates. These changes were counteracted by TQ co-incubation as TQ attenuated pyrogallol-induced impairment in vascular reactivity in a dose-dependent manner. Furthermore, TQ showed potent antioxidant activity as well as causing a significant increase in NOx and cNOS activity, and depression in iNOS activity. These results suggest that TQ can protect against pyrogallol-induced endothelial dysfunction which probably results from its potent antioxidant capacity that leads to an increase in NO production as well as its ability to enhance the generation and bioavailability of NO.

Anti-inflammatory and antioxidant activity of thymoquinone in a rat model of acute bacterial prostatitis

Prostatitis plays a major role in morbidity and mortality related to prostate diseases. The aim of this study was to detect whether thymoquinone (TQ) could ameliorate oxidative damage and the proliferative response induced by Escherichia coli ( E. coli) in rats. A total of 42 adult male Wistar rats were used. The rats were randomly divided into seven groups (three treatment groups, three infected groups and one control group). Control group received saline and was killed 24 h after saline administration. Infected rats were killed after 24, 48 and 72 h following direct injection of E. coli into the prostate. Treatment groups were administered with 10 mg/kg dose of TQ intraperitoneally following E. coli injection and after 24 and 48 h following E. coli injection. The rats were killed at 24, 48 and 72 h after the first drug administration. Each group was compared with each other and with the control group. In addition, infected groups were compared with treatment groups. Our findings show that the treatment with TQ has a protective effect against bacterial prostatitis-induced tissue injury. Increase in malondialdehyde levels and histological damage caused by E. coli were improved markedly with TQ treatment. TQ treatment particularly increased the activity of glutathione peroxidase and decreased the activities of catalase and superoxide dismutase. These observations might be attributed, at least in part, to the antioxidant effect of TQ and suggest that it could be a clinically valuable agent in the prevention of acute prostatitis caused by E. coli.

Thymoquinone improves aging-related endothelial dysfunction in the rat mesenteric artery

Aging-related endothelial dysfunction is characterized by blunted nitric oxide (NO)- and endothelium-derived hyperpolarizing factor (EDHF)-mediated relaxations in arteries, which may be due, at least in part, to increased oxidative stress. Endothelial dysfunction will promote the initiation and development of major cardiovascular diseases such as atherosclerosis and hypertension. Thymoquinone (TQ) is the most active constituent of the volatile oil of Nigella sativa seeds with well-documented antioxidative properties and vasodilator effects. This study determined whether TQ improves the endothelial function in middle-aged rats. Control young rats (16 weeks) received solvent (ethanol, 3% v/v), and middle-aged rats (46 weeks) either solvent or TQ (10 mg/kg/day) in the drinking water. Mesenteric artery reactivity was determined in organ chambers, vascular oxidative stress by dihydroethidine and MitoSOX staining, and expression of target proteins by immunohistochemical staining. Aging-related blunted NO- and EDHF-mediated responses were associated with downregulation of endothelial NO synthase (eNOS) and calcium-activated potassium channels (SK(Ca) and IK(Ca)) expression. Endothelial dysfunction was also associated with oxidative stress and an upregulation of angiotensin II and AT1 receptor expressions. Intake of TQ for 14 days restored NO- and EDHF-mediated relaxations, normalized oxidative stress, the expression level of eNOS, SK(Ca), IK(Ca), and the components of the angiotensin system in the mesenteric artery of middle-aged rats. Thus, TQ improves endothelial function in aging, at least in part, through inhibition of oxidative stress and normalization of the angiotensin system. TQ may represent a novel therapeutic approach for aging-associated vascular diseases.

Protective effects of thymoquinone on vancomycin-induced nephrotoxicity in rats

AIM

Oxidative stress has been implicated as a potential responsible mechanism in the pathogenesis of vancomycin (VCM)-induced renal toxicity. Therefore, we aimed to investigate the protective effect of thymoquinone (TQ) against VCM-induced nephrotoxicity by tissue oxidant/antioxidant parameters and histological changes in rats.

MATERIALS AND METHODS

Wistar albino rats were randomly separated into four groups consisting of seven rats per group. The groups had normal saline (control group), VCM, VCM and TQ and TQ, respectively. VCM was injected intraperitoneally at a dose of 200 mg/kg and continued at 12-h intervals for 7 days. TQ was injected intraperitoneally at a dose of 10 mg/kg and continued at 24 h intervals for 8 days. Animals were killed and blood samples were analyzed for the levels of serum blood urea nitrogen (BUN) and creatinine (Cr). Kidney specimens were analyzed for levels of malondialdehyde (MDA) and activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) as well as for histopathological changes.

RESULTS

We found that the levels of serum BUN, Cr and kidney tissue MDA were increased in the VCM group. Activities of SOD and GSH-Px in kidney tissue were decreased. TQ administration ameliorated significantly these changes.

CONCLUSION

These results indicate that the TQ produces a protective mechanism against VCM-induced nephrotoxicity and suggest a role of oxidative stress in pathogenesis.

Review on molecular and therapeutic potential of thymoquinone in cancer

Thymoquinone (TQ) is the predominant bioactive constituent present in black seed oil (Nigella sativa) and has been tested for its efficacy against cancer. Here, we summarize the literature about TQ's molecular mechanism of action and its ability to induce apoptosis and inhibit tumor growth in preclinical models. TQ has anti-inflammatory effects, and it inhibits tumor cell proliferation through modulation of apoptosis signaling, inhibition of angiogenesis, and cell cycle arrest. Chemosensitization by TQ is mostly limited to in vitro studies, and it has potential in therapeutic strategy for cancer. The results favor efficacy and enhancement of therapeutic benefit against tumor cells resistant to therapy based on cellular targets that are molecular determinants for cancer cell survival and progression. There have been attempts to synthesize novel analogs of TQ directed toward superior effects in killing tumor cells with more enhanced chemosensitizing potential than parent TQ compound. Based on published reports, we believe that further in-depth studies are warranted including investigation of its bioavailability and Phase I toxicity profiling in human subjects. The results from such studies will be instrumental in advancing this field in support of initiating clinical trials for testing the effects of this ancient agent in cancer therapy.

Protective effects of thymoquinone against methotrexate-induced testicular injury

Thymoquinone is the major active component derived from Nigella sativa. Methotrexate is a folic acid antagonist widely used in clinic. Aim of this study was to investigate the possible protective role of thymoquinone on testicular toxicity of methotrexate. Experiments were performed on male C57BL/6 mice (6 weeks old, 20 ± 2 g). The animals were divided into four groups with six mice in each group. Equivalent volumes of saline were injected intraperitoneally (i.p.) in the control group. In the thymoquinone group, mice received thymoquinone i.p. with a dose of 10 mg/kg/day for 4 days. Mice in the methotrexate group received single dose of methotrexate i.p., with a dose of 20 mg/kg. Finally, in the methotrexate plus thymoquinone group, in the first and the following 3 days after methotrexate administration, thymoquinone was injected with a dose of 10 mg/kg/day, i.p. At the end of the experiment, the left testis was quickly removed and divided into two parts for histological examination and biochemical analysis. Methotrexate alone increased total antioxidant capacity and myeloperoxidase activity compared to the controls. Thymoquinone treatment decreased total antioxidant capacity and prevented the increase in the myeloperoxidase activity. Light microscopy showed in mice that receiving methotrexate resulted in interstitial space dilatation, edema, severe disruption of the seminiferous epithelium and reduced diameter of the seminiferous tubules. Administration of thymoquinone reversed histological changes of methotrexate significantly. We suggest that thymoquinone use may decrease the destructive effects of methotrexate on testicular tissue of patients using this agent.