TLR4/ MyD88/NF-κB signaling pathway involved in the protective effect of diacerein against lung fibrosis in rats.

PURPOSE: Pulmonary fibrosis (PF) is an inescapable problem. Diacerein, a chondro-protective drug, has antioxidant and anti-inflammatory effects. Its effect on PF injury has not yet been fully clarified. Therefore, the current study aimed to detect its protective effect on lung tissue with the explanation of possible underlying mechanisms. METHODS: Adult male albino rats were assigned to four groups: control group, diacerein control group, PF non-treated group, and PF diacerein pretreated group. Lung tissue oxidative stress parameters, inflammatory biomarkers mainly Toll-like receptors-4 (TLR4), and myeloid differentiation factor 88 (MyD88) levels were determined. Histopathological examination of lung tissue and immunohistochemical studies of nuclear factor-kappa B (NF-κB), and transforming growth factor- ß (TGF-ß) were also done. RESULTS: Diacerein pretreatment has the ability to restore the PF damaging effect, proved by the reduction of the oxidative stress and lung tissue inflammation via downregulation of TLR4/NF-κB signaling pathway together with the restoration of TGF-ß level and improvement of the histopathological and immunohistochemical study findings in the lung tissue. CONCLUSION: These results suggested the protective effect of diacerein on PF relies on its antioxidant and anti-inflammatory effects reducing TLR4/NF-κB signaling pathway.

Mirabegron alleviates acetic acid-induced colitis in rats: Role of adiponectin and GSTM1/GSH detoxification pathway.

The prevalence of the debilitating chronic disease ulcerative colitis (UC) is increasing significantly. Mirabegron is a selective beta-3 adrenergic receptor (ß-3 AR) agonist used to treat an overactive bladder. Previous reports have demonstrated the antidiarrheal effect of ß-3AR agonists. Therefore, the current study aims to investigate the potential symptomatic effects of mirabegron on an experimental colitis model. The effects of oral administration of mirabegron (10 mg/kg) for seven days on rats receiving intra-rectal acetic acid instillation on the sixth day were examined using adult male Wistar rats. Sulfasalazine was utilized as a reference medication. Gross, microscopic, and biochemical observations of the experimental colitis were performed. The quantity and mucin content of goblet cells were found to have significantly decreased in the colitis group. In the colons of rats administered mirabegron, the number of goblet cells and the optical density of its mucin content increased. Mirabegron's ability to increase adiponectin in serum and decrease glutathione, GSTM1, and catalase in the colon may account for its protective effects. In addition, mirabegron decreased the expression of the proteins caspase-3 and NF-κB p65. It also prevented the activation of their upstream signaling receptors TLR4 and p-AKT by acetic acid administration. In conclusion, mirabegron prevented acetic acid-induced colitis in rats, possibly due to its antioxidant, anti-inflammatory, and antiapoptotic properties.

Pregnenolone Inhibits Doxorubicin-Induced Cardiac Oxidative Stress, Inflammation, and Apoptosis-Role of Matrix Metalloproteinase 2 and NADPH Oxidase 1.

The clinical usefulness of doxorubicin (DOX) is limited by its serious adverse effects, such as cardiotoxicity. Pregnenolone demonstrated both anti-inflammatory and antioxidant activity in animal models. The current study aimed to investigate the cardioprotective potential of pregnenolone against DOX-induced cardiotoxicity. After acclimatization, male Wistar rats were randomly grouped into four groups: control (vehicle-treated), pregnenolone (35 mg/kg/d, p.o.), DOX (15 mg/kg, i.p, once), and pregnenolone + DOX. All treatments continued for seven consecutive days except DOX, which was administered once on day 5. The heart and serum samples were harvested one day after the last treatment for further assays. Pregnenolone ameliorated the DOX-induced increase in markers of cardiotoxicity, namely, histopathological changes and elevated serum levels of creatine kinase-MB and lactate dehydrogenase. Moreover, pregnenolone prevented DOX-induced oxidative changes (significantly lowered cardiac malondialdehyde, total nitrite/nitrate, and NADPH oxidase 1, and elevated reduced glutathione), tissue remodeling (significantly decreased matrix metalloproteinase 2), inflammation (significantly decreased tumor necrosis factor-α and interleukin 6), and proapoptotic changes (significantly lowered cleaved caspase-3). In conclusion, these findings show the cardioprotective effects of pregnenolone in DOX-treated rats. The cardioprotection achieved by pregnenolone treatment can be attributed to its antioxidant, anti-inflammatory, and antiapoptotic actions.

Agomelatine ameliorates cadmium-induced toxicity through the modification of HMGB-1/TLR-4/NFκB pathway.

Cadmium (Cd) has potential hazards on human beings. Consequently, this study was performed to explore the protective effects of agomelatine (AGO), a melatonin receptor agonist, against Cd-induced toxicity in rats. AGO (40 mg/kg/day) was administered orally concomitant with intra peritoneal injection of Cd (0.4 mg/kg/day) for 14 days. Then, blood, biochemical parameters and histological examination of affected organs including, heart and testis, were evaluated. Interestingly, AGO significantly counteracted Cd-induced elevation of serum cardiac enzymes. Similarly, AGO significantly improved the deterioration of serum testosterone level with Cd administration. The oxidative balance was corrected by AGO, as evidenced by decrease malondialdehyde (MDA), and superoxide dismutase activity in cardiac and testicular tissues. Additionally, AGO increased silent information regulator 1 protein (SIRT-1) and decreased High mobility group box 1 (HMGB1), Toll like receptor-4 (TLR-4), and Myd88 levels that subsequently reduced expression of nuclear factor-κB (NF-κB). Moreover, level of apoptotic marker; caspase-3 was inhibited by AGO. In accordance with the biochemical and molecular results, AGO restored structure of cardiac myofibers and seminiferous tubules. Collectively, AGO mitigated cardiac and testicular toxicity of Cd via modulation of SIRT-1/HMGB1 and its downstream pathway.

Aprepitant exerts anti-fibrotic effect via inhibition of TGF-ß/Smad3 pathway in bleomycin-induced pulmonary fibrosis in rats.

Bleomycin is a well-recognized antineoplastic drug. However, pulmonary fibrosis (PF) is considered to be the principal drawback that greatly limits its use. Here, we sought to investigate ability of the neurokinin receptor 1 blocker, aprepitant, to prevent PF caused by bleomycin. Male adult Wistar rat groups were given a single intratracheal injection of bleomycin, either alone or in combination with aprepitant therapy for 3 or 14 days. Collagen deposition and a rise in transforming growth factor beta (TGF-ß) immunoreactivity in lung tissue serve as evidence of bleomycin-induced PF. The serum levels of lactate dehydrogenase, alkaline phosphatase, and total antioxidant improved after aprepitant therapy.Additionally, it reduced the protein expressions of interferon alpha, tumor necrosis factor alpha, and lung lipid peroxidation. Moreover, aprepitant treatment led to an increase in the antioxidant indices glutathione, glutathione peroxidase, and catalase. Aprepitant is postulated to protect against bleomycin-induced PF by decreasing TGF-ß, phosphorylating Smad3, and increasing interleukin 37, an anti-fibrotic cytokine, and G Protein-coupled Receptor Kinase 2. Aprepitant for 14 days considerably exceeded aprepitant for 3 days in terms of improving lung damage and having an anti-fibrotic impact. In conclusion, aprepitant treatment for 14 days may be used as an adjuvant to bleomycin therapy to prevent PF, mostly through inhibiting the TGF-/p-Smad3 fibrotic pathway.

Involvement of NOX-4/JAK/STAT pathway in the protective effect of aprepitant against diclofenac-induced renal toxicity.

AIMS: Aprepitant, a neurokinin-1 (NK1) receptor antagonist, is a clinically approved anti-emetic drug. Recently, inhibition of the NK1 receptor has been reported as a potential nephroprotective strategy. We aimed to assess the pharmacological mechanisms of aprepitant against diclofenac (DIC)-induced renal toxicity. MAIN METHODS: An in vivo study was conducted using twenty-four male Wistar rats, divided into 4 groups. Aprepitant was administered for 5 days (5 mg/kg/day) with or without DIC which was given on the 4th and 5th days (50 mg/kg, i.p.). At the end of the study, renal function biomarkers, renal oxidative parameters, prostaglandin E (PGE-2), and NADPH oxidase (NOX-4) were measured. Histopathological changes as well as expression of renal inflammatory and apoptotic markers (tumor necrosis factor alpha (TNF-α) and caspase-3) were investigated. KEY FINDINGS: DIC caused significant renal damage, as evidenced by deterioration of renal functions, oxidative stress, inflammatory and apoptotic markers, and confirmed by histopathological findings. Pretreatment with aprepitant successfully ameliorated and improved all biochemical and molecular parameters induced by DIC. Moreover, aprepitant restored the decrease in renal PGE-2 concentration and inhibited DIC-activated Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling in renal tissues. SIGNIFICANCE: The protective effect of aprepitant is possibly attributed to its anti-oxidant and anti-inflammatory roles via the NOX-4/JAK/STAT pathway.

Therapeutic effect of rupatadine against l-arginine-induced acute pancreatitis in rats: role of inflammation.

Acute pancreatitis (AP) is an abrupt inflammatory disorder causing high morbidity and mortality. As AP is an insidious medical emergency, a curative modality is required instead of a preventive measure. Thus, we investigated the possible curative effect of rupatadine on a rat model of AP. Rupatadine is a potent histamine receptor 1 (H1R) and platelet-activating factor (PAF) blocker. We used four groups of six Wistar rats as follows: the control group received vehicle; the rupatadine control group received rupatadine as 6 mg/kg orally; the AP group received l-arginine intraperitoneally, and the treatment group received rupatadine at 1, 6, and 24 h after l-arginine injection. The levels of serum amylase, pancreatic oxidative parameters, and pancreatic cytokines were measured. PAF, histamine, and myeloperoxidase levels were determined in the pancreas. Histopathological and immunohistochemical examinations were performed to determine nuclear factor kappa-B (NF-κB) and caspase 3 expressions. Oxidative damage and severe inflammation were detected in the pancreas of the AP group. Rupatadine reduced the oxidative damage and the levels of proinflammatory cytokines, PAF, histamine, myeloperoxidase, NF-κB, and caspase 3 expressions. It restored the pancreatic acini to almost normal condition. Rupatadine induced important anti-inflammatory and antiapoptotic effects against l-arginine-induced AP.

Rupatadine protects the intestinal mucosa from injury by 5-flurouracil via modulation of inflammation, apoptosis and intestinal permeability.

Fluorouracil (5-FU) is a widely used chemotherapeutic agent in various malignant tumors. However, intestinal toxicity is considered the irritant unavoidable adverse effect during the course therapy. The aim of the current study was to screen the effect of a new selective histamine receptor 1 blocker and platelet-activating factor (PAF) blocker on 5-FU induced intestinal toxicity. Five groups (6 rats each) of adult male rats (Wistar) were arranged as follows: (1) control group that was treated with carboxymethylcellulose, (2) a group that received rupatadine (higher dose) only, (3) a group that received 5-FU and (4) and (5) groups that received 5-FU plus lower or higher dose rupatadine, respectively. At end of the experiment, we determined intestinal malondialdehyde (MDA), glutathione reduced (GSH), nitric oxide (NO), tumor necrosis factor (TNF-α), interleukin 1ß, 6, 10 (IL-1ß, IL-6, IL-10), PAF, histamine, myeloperoxidase, cysteine-aspartic acid protease-3 (caspase-3), and nuclear factor kappa B (NF-κB) as well as the histological analysis. 5-FU injection caused marked elevation of MDA, NO, TNF-α, IL-1ß, IL-6, PAF, histamine, myeloperoxidase, caspase-3, and NF-κB expressions. The intoxicated animals showed deficient GSH and IL-10 along with significant loss of villi, disorganized crypts, and inflammatory cell infiltration. Rupatadine pretreatment reduced the previously mentioned parameters, preserved a nearly normal intestinal mucosa picture with replenished GSH and elevated IL-10. In conclusion, rupatadine is a dual histamine receptor 1, and a PAF blocker could reduce 5-FU-induced oxidative damage, inflammation, apoptosis, and ulceration of the intestinal epithelium. Rupatadine may be a valuable modality to decrease 5-FU induced intestinal mucositis.

Antifibrotic effects of bezafibrate and pioglitazone against thioacetamide-induced liver fibrosis in albino rats.

Activation of hepatic stellate cells is a central event in hepatic fibrogenesis that offers multiple potential sites for therapeutic interventions. Peroxisome proliferator-activated receptors are implicated in liver fibrosis. We aimed to evaluate the effect of bezafibrate and pioglitazone on a thioacetamide (TAA) rat model of liver fibrosis and to clarify the possible underlying mechanisms. Rats received intraperitoneal injections of TAA for 6 weeks. Daily oral treatments with bezafibrate or pioglitazone were started with the first day of TAA intoxication. Serum liver function tests, hepatic malondialdehyde (MDA), total nitrite and nitrate (NOx), superoxide dismutase, and hepatic histopathology were assessed to evaluate hepatic damage. Alpha smooth muscle actin (α-SMA) and tissue inhibitor metalloproteinase-1 (TIMP-1) and caspase-3 were also assessed. The TAA group experienced significant deterioration of liver functions, increased oxidative stress, and increased liver tissue NOx. Administration of bezafibrate or pioglitazone resulted in significant improvement of all liver functions and reduced oxidative stress in hepatic tissues. Only administration of bezafibrate significantly reduced NOx levels. Liver tissues from the TAA-treated group showed disrupted normal architecture. Administration of bezafibrate or pioglitazone attenuated this picture. Stronger α-SMA expression was detected in the TAA group. Treatment with bezafibrate or pioglitazone decreased the α-SMA expression.

Paeonol protects against testicular ischaemia-reperfusion injury in rats through inhibition of oxidative stress and inflammation.

Ischaemia-reperfusion (IR) is the most common form of testicular injury that results in oxidative damage and inflammation ending by subinfertility. Paeonol, a natural phenolic compound, exhibits antioxidant and anti-inflammatory effects. Thus, the present study investigated the role of paeonol in rat testicular IR injury. Thirty adult Wistar rats were randomly divided into five groups; sham, sham treated with paeonol, IR injury, and IR pre-treated with paeonol at low and high doses. Serum testosterone and testicular levels of malondialdehyde and reduced glutathione (GSH) besides superoxide dismutase (SOD) activity were determined. Gene quantifications for tumour necrosis factor-α (TNF-α), hypoxia-inducible factor-1α (HIF-1α) and heat shock protein 70 (HSP70) were also assessed. Histopathological pictures and the immunohistochemical expression of testicular nuclear factor erythroid 2-related factor 2 (Nrf2), interleukin-1ß (IL-1ß) and interleukin-6 (IL-6) were shown. Pre-treatment with paeonol prevented the drop in serum testosterone, alongside with improvement of testicular malondialdehyde and GSH levels plus SOD activity. Paeonol regained the normal spermatogenesis with prevention of IR-induced increase in TNF-α, HIF-1α and HSP70 gene expression besides IL-1ß and IL-6 immunostaining and reduction in Nrf2 protein expression. Paeonol exerted a dose-dependent beneficial effect on testicular IR injury. This effect was achieved by its antioxidant and anti-inflammatory effects.

Mechanisms underlying the protective effect of leukotriene receptor antagonist montelukast against doxorubicin induced testicular injury in rats.

The obligatory use of cytotoxic drugs to face the malignant tumors results in survivors that suffer from long term health problems. Fertility problems, especially in young boys, exert one of the major consequences of chemotherapy treatment that needs resolution. We investigate the potential effect of the cysteinyl leukotriene receptor antagonist montelukast on doxorubicin-induced testicular damage. Five groups of adult Wistar male rats were subjected to the following treatment; vehicle for the control group, montelukast (20 mg/kg orally daily for 10 days) for the drug control, doxorubicin (12 mg/kg intraperitoneal injection once at 5th day) for the toxic group, montelukast at 10 mg/kg + doxorubicin, montelukast at 20 mg/kg + doxorubicin. The period of the experiment was 10 days administration of montelukast, while doxorubicin was injected at the 5th day. Results of serum testosterone, testicular lipid peroxidation, antioxidant status, and histopathology revealed protection of montelukast against doxorubicin-induced testicular damage. The pro-apoptotic caspase 3 and the pro-inflammatory tumor necrosis factor-alpha were examined immunohistochemically and showed a significant decrease with montelukast treatment as compared to doxorubicin group. Doxorubicin increased gene expression of matrix metalloproteinase 9 and decreased peroxisome proliferator activated receptor gamma. Montelukast treatment restored their expressions to normal values. In conclusion, montelukast administration can ameliorate the testicular damage induced by doxorubicin based on its anti-inflammatory, antioxidant and anti-apoptotic effects as well as by of modulation of important genes expression.

Role of Nrf2/HO-1 and PI3K/Akt Genes in the Hepatoprotective Effect of Cilostazol.

BACKGROUND: Cilostazol, a phosphodiesterase 3 inhibitor (PDE3I), is a platelet aggregation inhibitor and vasodilator that is useful for treating intermittent claudication. Experimental studies have shown that cilostazol has potent anti-inflammatory, anti-oxidant effects effects. OBJECTIVES: Although the hepatoprotective effect cilostazol has been studied, the molecular mechanisms of such protection, including: the nuclear factor-erythroid 2-related factor 2 (Nrf2) / hemoxygenase (HO-1) and the phosphoinositide 3-kinase (PI3K) /serine/threonine kinase (Akt) pathways are not fully explored, which is the aim of this study. METHODS: To achieve the aim of this study, 35 rats were grouped into: control groups, liver injury group (model- non treated: injected with thioacetamide (TAA), 150 mg/kg, i.p.), and two cilostazoltreated groups (treated with cilostazol 10 and 50 mg/kg, p.o.). The rats were treated for 8 days and injected with TAA on the 7th day of the experiment and sacrificed 48 hours after TAA injection. RESULTS: The model group showed evidence of liver injury as indicated by the elevation of liver enzymes and confirmed by histopathological findings. TAA-induced liver injury was accompanied by down-regulation of the cytoprotective pathways: PI3K/Akt and Nrf2/HO-1 mRNAs. Cilostazol administration ameliorated TAA-induced liver injury, where it caused a significant improvement in the activity of liver enzymes as well as in the histopathological changes. Such an effect was associated with a significant increase in the expression of PI3K/Akt and Nrf2/HO-1 mRNAs as detected by Real-time reverse transcription polymerase chain reaction (RT-PCR). CONCLUSION: Cilostazol protected rats against TAA hepatotoxicity through up-regulation of PI3K/Akt and Nrf2/HO-1 gene expression.

Cilostazol alleviates streptozotocin-induced testicular injury in rats via PI3K/Akt pathway.

AIMS: Male infertility prevalence is higher in diabetic patients. Those patients exhibit testicular oxidative damage due to sustained hyperglycemia and inflammation. The study has investigated the efficacy of cilostazol, a phosphodiesterase 3 inhibitor, on testicular damage of diabetic rats. MAIN METHODS: Streptozotocin-induced diabetes in rats was used as a model. Six control male rats and 24 diabetic male rats were divided into the following: diabetic, cilostazol at low dose, cilostazol at high dose, and sildenafil treated rat groups. Treatment period was 4 weeks. Then, serum testosterone, testicular oxidative parameters, and testicular oxidant defenses were assayed. Real time PCR was done for quantification of Phosphoinositide 3-kinase (PI3K), Akt, and nuclear factor (NF)-κB mRNA. Expression of testicular inducible nitric oxide synthase (iNOS) was assessed. KEY FINDINGS: Diabetes negatively affected the testicular tissue as evident by biochemical analysis and histopathology. Four weeks of cilostazol or sildenafil treatment improved anti-oxidative capacity, ameliorated lipid peroxidation and the pro-inflammatory iNOS expression in testicular tissue. Testosterone level and the spermatogenesis showed marked improvement. Quantitative mRNA expression showed an elevation in PI3K and Akt by cilostazol with decreasing in NF-κB level by both drugs. SIGNIFICANCE: Our findings suggest the beneficial role of cilostazol and sildenafil in diabetic testicular damage dependent on anti-inflammatory and anti-oxidant effects.

STAT3 and Nrf2 pathways modulate the protective effect of verapamil on lung injury of diabetic rats.

OBJECTIVE: We aimed to assess the protective role of verapamil, L-type calcium channel blockers, against early lung damage in diabetic rats. Lung injury has recently been recognized as a consequent complication of diabetes mellitus. Hyperglycemia induces inflammatory changes in lung tissue early in the disease. METHODS: Twenty four adult male rats were grouped into control, diabetic, diabetic treated with verapamil, and verapamil control. Streptozotocin (STZ) was used to induce diabetes. Oxidative parameters and antioxidative mechanisms were assessed in lung homogenate. Tumor necrosis factor alpha (TNFα) protein was measured as a pro-inflammatory mediator. Signal transducer and activator of transcription 3 (STAT3) gene expression and nuclear erythroid factor 2 (Nrf2) immunoexpression were screened. RESULTS: The lung showed oxidative damage and inflammatory infiltration in STZ diabetic rats early at 2 weeks. The parameters significantly improved in lung tissue treated with verapamil. Histopathology of the lung tissue confirmed the results. Inhibition of STAT3/TNFα pathway was involved in the protection offered by verapamil. Activation of Nrf2 together with an increasing antioxidant capacity of diabetic lung significantly ameliorates the injury induced by diabetes. CONCLUSIONS: Verapamil afforded protection in diabetic lung injury. The protection was mediated by the anti-inflammatory and antioxidant effects of verapamil.