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.

Carnosine Potentiates Doxorubicin-Induced Cytotoxicity in Resistant NCI/ADR-RES Cells by Inhibiting P-Glycoprotein-In Silico and In Vitro Evidence.

The activity of the P-glycoprotein (P-gp) transporter encoded by the ABCB1 gene confers resistance to anticancer drugs and contributes to cancer-related mortality and morbidity. Recent studies revealed the cytotoxic effects of the endogenous dipeptide carnosine. The current study aimed to investigate the role of carnosine as a potential inhibitor of P-gp activity. We used molecular docking and molecular dynamic simulations to study the possible binding and stability of carnosine-P-gp interactions compared with verapamil. In vitro assays using doxorubicin-resistant NCI/ADR-RES cells were established to test the effects of carnosine (10-300 µM) on P-gp activity by the rhodamine-123 efflux assay and its effect on cell viability and doxorubicin-induced cytotoxicity. Verapamil (10 µM) was used as a positive control. The results showed that carnosine binding depends mainly on hydrogen bonding with GLU875, GLN946, and ALA871, with a higher average Hbond than verapamil. Carnosine showed significant but weaker than verapamil-induced rhodamine-123 accumulation. Carnosine and verapamil similarly inhibited cell viability. However, verapamil showed a more significant potentiating effect on doxorubicin-induced cytotoxicity than a weaker effect of carnosine at 300 µM. These results suggest that carnosine inhibits P-gp activity and potentiates doxorubicin-induced cytotoxicity at higher concentrations. Carnosine might be a helpful lead compound in the fight against multidrug-resistant cancers.

Paeonol Protects against Methotrexate Hepatotoxicity by Repressing Oxidative Stress, Inflammation, and Apoptosis-The Role of Drug Efflux Transporters.

Methotrexate (MTX) is an effective chemotherapeutic agent against a wide range of tumors and autoimmune diseases; however, hepatotoxicity limits its clinical use. Oxidative stress and inflammation have been implicated in the pathogenesis of MTX-induced hepatotoxicity. Paeonol is a natural phenolic compound reported for its antioxidant and anti-inflammatory properties. The current study aimed to investigate the protective effect of paeonol against MTX-induced hepatotoxicity in rats and various mechanisms that underlie this postulated effect. Paeonol was administered orally in a dose of 100 mg/kg, alone or along with MTX, for 10 days. Hepatotoxicity was induced via a single intraperitoneal dose of MTX (20 mg/kg) on day 5 of the experiment. Concomitant administration of paeonol with MTX significantly ameliorated distorted hepatic function and histological structure, restored hepatic oxidative stress parameters (MDA, NO, and SOD), and combated inflammatory response (iNOS and TNF-α). Additionally, paeonol enhanced cell proliferation and survival, evidenced by upregulating the proliferating cell nuclear antigen (PCNA) and suppressing apoptosis and the disposition of collagen fibers in rat livers treated with MTX. Importantly, paeonol upregulated the drug efflux transporters, namely P-glycoprotein (P-gp) and the multidrug resistance-associated protein 2 (Mrp-2) in MTX-treated rats. In conclusion, paeonol offered a potent protective effect against MTX-induced hepatotoxicity through suppressing oxidative stress, inflammation, fibrosis, and apoptosis pathways, along with P-gp and Mrp-2 upregulation.

Paeonol Attenuates Hepatic Ischemia/Reperfusion Injury by Modulating the Nrf2/HO-1 and TLR4/MYD88/NF-κB Signaling Pathways.

Hepatic ischemia/reperfusion (HIR) is the most common type of liver injury following several clinical situations. Modulating oxidative stress and inflammation by Nrf2/HO-1 and TLR4/MYD88/NF-κB pathways, respectively, is involved in alleviating HIR injury. Paeonol is a natural phenolic compound that demonstrates significant antioxidant and anti-inflammatory effects. The present study explored the possible protective effect of paeonol against HIR injury and investigated its possible molecular mechanisms in rats. Rats were randomly divided into four groups: sham-operated control, paeonol-treated sham-operated control, HIR untreated, and HIR paeonol-treated groups. The results confirmed that hepatic injury was significantly aggravated biochemically by elevated serum levels of alanine transaminase and aspartate transaminase, as well as by histopathological alterations, while paeonol reduced the increase in transaminases and alleviated pathological changes induced by HIR. Additionally, paeonol inhibited the HIR-induced oxidative stress in hepatic tissues by decreasing the upraised levels of malondialdehyde and nitric oxide and enhancing the suppressed levels of reduced glutathione and superoxide dismutase activity. Furthermore, paeonol activated the protective antioxidative Nrf2/HO-1 pathway. The protective effect of paeonol was associated with inhibiting the expression of the inflammatory key mediators TLR4, MYD88, NF-κB, and TNF-α. Finally, paeonol inhibited the increased mRNA levels of the pro-apoptotic marker Bax and enhanced the reduced mRNA levels of the anti-apoptotic marker Bcl-2. Taken together, our results proved for the first time that paeonol could protect against HIR injury by inhibiting oxidative stress, inflammation, and apoptosis.

Guanosine protects against glycerol-induced acute kidney injury via up-regulation of the klotho gene.

Objectives: Acute Kidney Injury (AKI) is characterized by a rapid and reversible decline in renal function with a rapid decrease in Glomerular Filtration Rate (GFR), which is associated with high mortality. Rhabdomyolysis accounts for 10-40% of AKI, to which the therapeutic approach is limited. Klotho is a protein that modulates sodium-phosphate co-transporters, ion channels that have been reported to have a renal protective effect. Guanosine, a purine nucleoside, has already been reported to have a renal protective effect; however, the mechanism of such protection and its relation to Klotho modification has not been evaluated yet. This study aims to evaluate the mechanism of the protective effect of guanosine against rhabdomyolysis-induced AKI and its relation to the expression of the Klotho gene. Materials and Methods: In the current study, rats were divided into three groups: control, glycerol-induced AKI, and guanosine-treated. Serum urea and creatinine levels, renal tissue Total Antioxidant Capacity (TAC), and Klotho and Cystatin C genes expression were evaluated. Furthermore, caspase-3 immunostaining and histopathological evaluations were done. Results: Results showed that guanosine treatment resulted in a significant reduction in serum urea and creatinine, Cystatin C genes expression, and caspase-3 immunoexpression, and an increase in TAC and Klotho genes expression. Results also revealed an improvement of renal histopathology when compared with the glycerol-induced AKI group. Conclusion: Guanosine may be a promising agent in the treatment of rhabdomyolysis-induced AKI. The proposed mechanism for guanosine may be through its ability to enhance Klotho gene expression in renal tissue, with subsequent antioxidant and anti-apoptotic activity.

Paeonol Protects Against Methotrexate-Induced Nephrotoxicity via Upregulation of P-gp Expression and Inhibition of TLR4/NF-κB Pathway.

Methotrexate (MTX) is a well-known anticancer drug that causes nephrotoxicity as a side effect. To investigate the mechanisms by which paeonol, a natural phenolic compound, can protect against MTX-induced nephrotoxicity, paeonol (100 mg/kg/day orally) was given to rats for 10 days, with or without MTX (20 mg/kg once i.p. at day 5). Compared to control, MTX caused nephrotoxic effects manifested by increased serum urea and creatinine and distortion in renal histological architecture, with a significant increase in the mean glomerular diameter and upregulation of kidney injury molecule-1. MTX caused oxidative stress manifested by decreasing reduced glutathione and superoxide dismutase while increasing malondialdehyde and nitric oxide. MTX also induced renal inflammation by upregulating TLR4, NF-κB, and IL-1ß and caused apoptosis by induction of caspase 3. Administering paeonol with MTX improved kidney functional and structural parameters, as well as all oxidative, inflammatory, and apoptotic markers tested. Interestingly, both MTX and paeonol increased the expression of the renal efflux transporter P-glycoprotein (P-gp) that helps in MTX elimination, and their drug combination further upregulated renal P-gp. In silico, paeonol was neither a substrate nor an inhibitor of P-gp, suggesting that its effect on P-gp is not on functional but on the expression level. In vitro, paeonol and MTX were administered to colon cancer cells and their combination caused a progressive cellular cytotoxic effect, which was dose-dependent with the increase of paeonol concentration. In conclusion, paeonol protects against MTX-induced nephrotoxicity through antioxidant, anti-inflammatory, and antiapoptotic mechanisms and might potentiate MTX chemotherapeutic efficacy.

Rupatadine ameliorated ulcerative colitis in rats via modulation of platelet-activatiweng factor/interleukin-6/vascular endothelial growth factor signalling pathway.

OBJECTIVES: This study aimed to analyse the potential effect of rupatadine (RUP) on ulcerative colitis (UC) induced by acetic acid (AA). METHODS: Forty male adult Wistar rats were divided into five groups: Control group: received vehicles for 14 days; AA model group: received AA at the 13th day; Sulfasalazine (SLZ) + AA group: received SLZ (250 mg/kg) for 14 days and AA at the 13th day; RUP-3 + AA group: received RUP (3 mg/kg/day) for 14 days and AA at the 13th day; and RUP-6 + AA group: received RUP (6 mg/kg/day) for 14 days and AA at the 13th day. Evidence of UC was assessed both macroscopically and microscopically. Oxidative stress markers (total antioxidant capacity and malondialdehyde), antioxidant enzyme (superoxide dismutase), histamine and platelet-activating factor (PAF) were determined. Immunohistochemical estimations of vascular endothelial growth factor (VEGF) and interleukin-6 (IL-6) were done. KEY FINDINGS: The AA group showed evidence of UC that was associated with a significant increase in oxidative stress, histamine and PAF levels with significant elevation in colonic VEGF and IL-6 immuno-expressions. RUP, in a dose-dependent manner, significantly ameliorated UC. CONCLUSION: RUP protects against UC by reducing oxidative stress and by regulating the PAF/IL-6/VEGF pathway.

Nitric Oxide Modulation as a Potential Molecular Mechanism Underlying the Protective Role of NaHS in Liver Ischemia Reperfusion Injury.

BACKGROUND: Liver IR is a frequent clinical complication with high morbidity and mortality. The present study evaluated the possible protective effect of sodium hydrosulfide (NaHS), a H2S donor, in IR-induced hepatic injury and explored the mechanisms of actions of the investigated drug. METHODS: Male albino rats (200-230 g) were divided into the following groups: group 1:Sham-operated non treated rats, group 2: IR non treated rats, group 3: L-NNA + IR rats, group 4: NaHS + IR rats, group 5: L-NNA + NaHS + IR rats. Blood samples were collected for ALT determination. Liver tissue samples were used for the assessment of GPx, catalase, SOD, MDA, total nitrites and TNF- α. Parts from the liver were fixed in 10% formalin solution for histopathological examination and immunohistochemical examination of iNOS, eNOS and caspase-3. RESULTS: NaHS protected the liver against IR. This hepatoprotection was associated with normalization of antioxidant enzyme activity and decrease in hepatic MDA, TNF-α and expression of caspase- 3 and iNOS. CONCLUSION: NaHS is hepatoprotective in IR injury. The hepatoprotective effects of NaHS are associated with antioxidant, anti-inflammatory and antiapoptotic effects. These effects are probably mediated via NO modulation.

Cardioprotective effects of bosentan in 5-fluorouracil-induced cardiotoxicity.

5-fluorouracil (5-FU) is a widely used chemotherapeutic agent but cardiotoxicity challenges its clinical usefulness. Thus, searching for more cardioprotective drugs is highly required to prevent the accompanied cardiac hazards. Up to date, the different mechanisms involved in 5-FU cardiotoxicity are still unclear and there is no evaluation of bosentan's role in controlling these cardiac complications. This forced us to deeply study and evaluate the possible cardiopreserving properties of bosentan and different mechanisms involved in mediating it. 32 Wistar albino rats were included in our experiment and induction of cardiotoxicity was performed via administration of 5-FU (150 mg/kg) on 5th day of the experiment by intraperitoneal (i.p.) injection with or without co-administration of bosentan (50 mg/kg/day) orally for 7days. Our data revealed that 5-FU could induce cardiotoxicity which was detected as significant increases of troponin I, lactate dehydrogenase (LDH), creatine kinase- MB (CK-MB), endothelin receptors, malondialdehyde (MDA), toll like receptor4 (TLR4), myeloid differentiation primary response 88 (MyD88), nuclear factor kappa B (NFκB), and caspase 3 levels. However, there is marked decrease in endothelial nitric oxide synthase (eNOS), reduced glutathione (GSH) and total antioxidant capacity (TAC). In addition, the histopathological examination showed severe toxic features of cardiac injury. Interestingly, co-administration of bosentan could ameliorate 5-FU-induced cardiotoxicity via improving the detected biochemical and histopathological changes besides modulation of TLR4/MyD88/NFκB signaling pathway, eNOS, and endothelin receptors. Bosentan had a significant cardioprotective effect against 5-FU induced cardiac damage. This effect may be attributed to its ability to inhibit endothelin receptors, stimulates eNOS, anti-oxidant, anti-inflammatory, anti-apoptotic properties with modulation of TLR4/MyD88/NFκB signaling pathway.

Protective mechanisms of telmisartan against hepatic ischemia/reperfusion injury in rats may involve PPARγ-induced TLR4/NF-κB suppression.

Hepatic ischemia-reperfusion (I/R) is an important cause of liver damage in many clinical situations. Toll-like receptor 4 (TLR4)/nuclear factor-kappa B (NF-κB) is an inflammatory pathway activated in hepatic I/R injury. Telmisartan, a selective angiotensin II type 1 receptor antagonist and peroxisome proliferator-activated receptor-gamma (PPARγ) partial agonist, can inhibit the expression of pro-inflammatory cytokines. The present work investigated the possible protective effect of telmisartan against hepatic I/R injury and explored its possible mechanisms in rats. Rats were divided into four equal groups: sham-operated control, telmisartan-treated sham-operated control, I/R untreated, and I/R telmisartan-treated groups. Hepatic injury was evaluated biochemically by serum activity of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and histopathological examination. Hepatic oxidative stress biomarkers, myeloperoxidase level, PPARγ and TLR4 mRNA expression, and NF-κB and active caspase 3 immunoexpression were determined. The study showed that telmisartan attenuated hepatic I/R, as evidenced by decreased serum ALT and AST activities and confirmed by improvement of the histopathological changes. The protective effect of telmisartan was associated with modulation of oxidative stress parameters, myeloperoxidase level, PPARγ and TLR4 mRNA expression, and NF-κB and caspase 3 immunoexpression. Taken together, the current study showed that telmisartan could protect the rat liver from I/R injury. This hepatoprotective effect was attributed to, at least in part, increase in PPARγ expression and suppression of TLR4/NF-κB pathway.

Protective effect of mirtazapine against acetic acid-induced ulcerative colitis in rats: Role of NLRP3 inflammasome pathway.

AIMS: Ulcerative colitis (UC) is an inflammatory bowel disease (IBD) that causes long-lasting inflammation on the innermost lining of the colon and rectum. Mirtazapine (MRT) is a well-known antidepressant that was proven to have anti-inflammatory activity; however, to date, its role has not been investigated in UC. The current study aimed to investigate the role and mechanism of MRT in UC. MAIN METHOD: Acetic acid (AA) was used for UC induction, and sulfasalazine (SLZ) was used as a positive control. Rats were divided into five equal groups; as follows; normal control, AA, SLZ (received SLZ in a dose of 250 mg/kg for 14 days), MRT10 (received MRT in a dose of 10 mg/kg/day for 14 days), and MRT30 (received MRT in a dose of 30 mg/kg/day for 14 days) groups. Macroscopic and microscopic examinations together with oxidative stress parameters evaluation were done. NOD-like receptors-3 (NLRP3), caspase-1, TNF-α, and nuclear factor kappa B (NF-κB) expression together with interleukin (IL)-1ß and IL-18 levels were examined. KEY FINDING: MRT, in a dose-dependent manner, prevented the macroscopic and microscopic colonic damage and corrected the oxidative stress induced by AA. Moreover, MRT decreased the colonic tissue NLRP3 inflammasome, caspase-1, NF-κB, TNF-α expressions, IL-1ß, and IL-18 levels that were elevated in colonic tissue by the AA. SIGNIFICANCE: MRT has a dose-dependent protective effect against UC that was mediated mainly by its anti-inflammatory activity with modulation of NLRP3/caspase-1 inflammatory pathway.

Dose-Dependent Cardioprotective Effect of Hemin in Doxorubicin-Induced Cardiotoxicity Via Nrf-2/HO-1 and TLR-5/NF-κB/TNF-α Signaling Pathways.

Doxorubicin (DOX) is one of the most widely used chemotherapeutic drugs, but its cardiotoxicity has been shown to be a dose-restricting factor during therapy. Finding new agents for reducing these complications is still in critical need. The current study aimed to evaluate the possible cardioprotective effect of hemin (HEM) in DOX-induced cardiotoxicity and exploring the role of toll like receptor-5/nuclear factor kappa-B/tumor necrosis factor-alpha (TLR-5/NF-κB/TNF-α) and nuclear factor erythroid 2-related factor-2/hemeoxygenase-1 (Nrf-2/HO-1) signaling pathways in mediating such effect. Wistar albino rats were randomly divided into five groups. They were administered DOX by interaperitoneal (i.p.) injection (15 mg/kg) on the 5th day of the experiment with or without HEM in different doses (2.5, 5, 10 mg/kg/day) i.p. for 7 days. Results showed that the DOX group had cardiotoxicity as manifested by a significant increase in cardiac enzymes, malondialdehyde (MDA), TLR-5, NF-κB, TNF-α, and cleaved caspase-3 levels with toxic histopathological changes. Based on these findings, HEM succeeded in reducing DOX-induced cardiotoxicity in a dose-dependent effect by stimulation of Nrf-2/HO-1 and inhibition of TLR-5/NF-κB/TNF-α pathways with subsequent antioxidant, anti-inflammatory, and anti-apoptotic effects.

Hesperidin opposes the negative impact of cyclophosphamide on mice kidneys.

The present investigation examined the prospective nephroprotective effect of hesperidin (HSN) in mice challenged with a single i.p. injection of cyclophosphamide (CPE) at a dose of 200 mg/kg. HSN (100 and 200 mg/kg/day, p.o.) was given for 10 days, starting 5 days prior to CPE administration. HSN significantly reduced the CPE-induced increments of serum creatinine and cystatin C. HSN also significantly reduced malondialdehyde, nitric oxide, Bax/Bcl-2 ratio, and caspase-3, and significantly raised total antioxidant capacity, and interleukin-10/tumor necrosis factor-α ratio in kidneys of mice received CPE. In addition, HSN significantly prevented the histopathological injury, and kidney injury molecule-1 expression in kidneys of mice given CPE. It was concluded that HSN guarded against nephrotoxic effect of CPE in mice by tackling oxidative/nitrative stress, inflammation, and apoptosis.

The Possible Contribution of P-Glycoprotein in the Protective Effect of Paeonol against Methotrexate-Induced Testicular Injury in Rats.

Paeonol, a phenolic ingredient in the genus Paeonia, possesses antioxidant and anti-inflammatory effects. Methotrexate (MTX) is a commonly used chemotherapeutic agent; however, its germ cell damage is a critical problem. P-glycoprotein (P-gp), an efflux transporter, is a member of the blood-testis barrier. The present study evaluated the protective effect of paeonol on MTX-induced testicular injury in rats with the exploration of its mechanism and the possible contribution of P-gp in such protection. Testicular weight, serum testosterone, and testicular P-gp levels were measured. Testicular oxidant/antioxidant status was evaluated via determining the levels of malondialdehyde, total nitrite, reduced glutathione, and superoxide dismutase activity. The inflammatory cytokine tumor necrosis factor-alpha (TNF-α) and the apoptotic marker caspase 3 were estimated immunohistochemically. Testicular histopathology and spermatogenesis scores were also examined. MTX caused histopathologically evident testicular damage with decreased testicular weight, testosterone level, and spermatogenesis score, as well as significant increases in oxidative, inflammatory, and apoptotic responses. Paeonol significantly restored testicular weight, testosterone level, spermatogenesis score, and oxidant/antioxidant balance. Moreover, paeonol increased the testicular P-gp level and significantly decreased TNF-α and caspase 3 immunostaining. In conclusion, paeonol offered a protective effect against MTX-induced testicular injury through its antioxidant, anti-inflammatory, and antiapoptotic effects, as well as by increasing testicular P-gp level.

Possible mechanisms mediating the protective effect of cilostazol in L-arginine induced acute pancreatitis in rats: role of cGMP, cAMP, and HO-1.

Acute pancreatitis (AP) is an inflammatory disorder with a high mortality rate. Cilostazol is a selective phosphodiesterase-3 inhibitor drug that is commonly used as an antiplatelet, antithrombotic, and vasodilator drug. It exhibits antioxidant, anti-inflammatory, and anti-apoptotic activities, but its effect on AP has not been fully elucidated yet. The present study aimed to investigate the effects of cilostazol on L-arginine-induced AP and the possible protective mechanisms. A rat model of AP was established by a single i.p. injection of 3-g/kg L-arginine on day 13 of the experiment. The treated groups received a single daily oral dose of either 100 or 300 mg/kg/day for 14 consecutive days. Rats with AP showed histopathological changes of pancreatic tissue injury together with increased serum amylase enzyme activity and decreased serum insulin, pancreatic adiponectin, and cGMP levels. Moreover, AP rats showed increased pancreatic inflammatory biomarker (TNF-α, VCAM-1, and MPO) levels with decreased anti-inflammatory IL-10 levels. In addition, oxidative stress biomarkers (MDA and NO) were increased in AP with decreased antioxidant SOD activity and GSH level. Moreover, HO-1 immunostaining was increased in the AP group. Cilostazol pretreatment reversed the histopathological change; decreased the amylase activity and the levels of TNF-α, VCAM-1, and MPO; and increased the levels of insulin, adiponectin, cGMP, cAMP, and IL-10. Moreover, cilostazol decreased MDA and NO but increased SOD and GSH. Lastly, cilostazol increased the HO-1 immunostaining more than in the AP group. These data suggest that cilostazol protects against L-arginine-induced AP, which may be related to an increase in cGMP, cAMP, and upregulation of HO-1 with subsequent anti-inflammatory and antioxidant properties.

Paeonol Attenuates Methotrexate-Induced Cardiac Toxicity in Rats by Inhibiting Oxidative Stress and Suppressing TLR4-Induced NF-κB Inflammatory Pathway.

Methotrexate (MTX) is a commonly used chemotherapeutic agent. Oxidative stress and inflammation have been proved in the development of MTX toxicity. Paeonol is a natural phenolic compound with various pharmacological activities including antioxidant and anti-inflammatory properties. The aim of the present study was to evaluate the protective effect of paeonol against MTX-induced cardiac toxicity in rats and to evaluate the various mechanisms that underlie this effect. Paeonol (100 mg/kg) was administered orally for 10 days. MTX cardiac toxicity was induced at the end of the fifth day of the experiment, with or without paeonol pretreatment. MTX-induced cardiac damage is evidenced by a distortion in the normal cardiac histological structure, with significant oxidative and nitrosative stress shown as a significant increase in NADPH oxidase-2, malondialdehyde, and nitric oxide levels along with a decrease in reduced glutathione concentration and superoxide dismutase activity compared to the control group. MTX-induced inflammatory effects are evidenced by the increased cardiac toll-like receptor 4 (TLR4) mRNA expression and protein level as well as increased cardiac tumor necrosis factor- (TNF-) α and interleukin- (IL-) 6 levels along with increased nuclear factor- (NF-) κB/p65 immunostaining. MTX increased apoptosis as shown by the upregulation of cardiac caspase 3 immunostaining. Paeonol was able to correct the oxidative and nitrosative stress as well as the inflammatory and apoptotic parameters and restore the normal histological structure compared to MTX alone. In conclusion, paeonol has a protective effect against MTX-induced cardiac toxicity through inhibiting oxidative and nitrosative stress and suppressing the TLR4/NF-κB/TNF-α/IL-6 inflammatory pathway, as well as causing an associated reduction in the proapoptotic marker, caspase 3.

The hepatoprotective effect of sitagliptin against hepatic ischemia reperfusion-induced injury in rats involves Nrf-2/HO-1 pathway.

BACKGROUND: Oxidative stress and inflammation play a key role in the development of hepatic ischemia reperfusion (HIR)-induced injury. Nuclear factor-erythroid 2-related factor-2 (Nrf-2) is a main regulator of numerous genes, encoding cytoprotective molecules including heme oxygenase-1 (HO-1). Sitagliptin (Sit) is an incretin enhancer acting via inhibition of dipeptidyl peptidase-4 (DPP-4) enzyme. This study was undertaken to investigate the ability of Sit to prevent the hepatic pathological changes of HIR induced injury and to modify Nrf-2 and its target HO-1. METHODS: Pringle's maneuver was used to induce total HIR in adult male rats that were randomly assigned into 4 groups. Group1 (sham-operated control), Group 2 (sham-operated + Sit-control group), Group 3 (HIR non-treated), and Group 4 (HIR + Sit). Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities together with hepatic contents of malondialdhyde (MDA), nitric oxide (NO) and reduced glutathione (GSH) and superoxide dismutase (SOD) activity were evaluated. Hepatic tissue mRNA of Nrf-2 and protein content of HO-1 along with histopathological examination and scoring of hepatic injury were performed. RESULTS: Sit caused a significant reduction in ALT and AST activities together with attenuation of HIR-induced histopathological liver injury. Effect of Sit was associated with decreased hepatic level of MDA and NO with increased GSH level and SOD activity. Non-treated rats with HIR showed an increase in Nrf-2 mRNA expression and HO-1 content in hepatic tissue which was further increased by Sit treatment. CONCLUSIONS: These results indicate that hepatoprotective activity of Sit against HIR is attributed at least in part to modulation of Nrf-2/ HO-1 signaling pathway.

Ameliorative effects of silymarin on HCl-induced acute lung injury in rats; role of the Nrf-2/HO-1 pathway.

OBJECTIVES: Aspiration is a common cause of acute lung injury (ALI), which lacks an effective treatment. Inflammation and oxidative stress play key roles in ALI development. Silymarin is an active extract of Silybum marianum plant seeds (milk thistle). Silymarin has potent anti-inflammatory and antioxidant effects; however its role in aspiration induced ALI has not been investigated. The aim of this study is to investigate the role of silymarin in the treatment of hydrochloric acid (HCl) aspiration induced ALI and explores its mechanisms of action. MATERIALS AND METHODS: The study included three groups of rats: Control non-treated group, ALI group (intra-tracheal HCl injected), and silymarin treated ALI group. White blood cells (WBCs) with differential count, oxidative stress parameters, B-cell lymphoma 2 (Bcl-2), transforming growth factor-beta (TGF-ß), cyclooxygenase 2 (COX-2), nuclear factor erythroid 2-related factor-2 (Nrf-2), and heme oxygenase-1 (HO-1) were investigated. Lung tissue histopathology and immunohistochemical expression of survivin and proliferating cell nuclear antigen (PCNA) were also examined. RESULTS: The results of the study showed that HCL caused histopathological changes in ALI with leukocytopenia and increased oxidative stress biomarkers. It increased TGF-ß, up-regulated mRNA expression of COX-2, Nrf-2, and HO-1 and increased survivin and PCNA but decreased Bcl-2. Silymarin ameliorated the histopathological lung injury with further up-regulation of Nrf-2 and HO-1 mRNA and decreased the inflammatory and fibrotic parameters together with up-regulation of the anti-apoptotic and the proliferation parameters. CONCLUSION: The protective effect of silymarin against ALI is mediated by Nrf-2/HO-1 pathway with subsequent antioxidant, anti-inflammatory, antiapoptotic, and proliferating activities.

Mechanism mediating the protective effect of diacerein in ischemia-reperfusion-induced testicular injury in rats.

AIMS: Torsion of the spermatic cord is a common urologic emergency and can lead to testicular necrosis and infertility. Diacerein (DIA) is interleukin-1b (IL-1b) blocker which has a protective role against myocardial ischemia-reperfusion, however, to-date this role has not been investigated in testicular ischemia- reperfusion (TIR). We aimed to investigate the role and mechanism of action of DIA in induced TIR. MAIN METHODS: DIA (50 mg/kg) was administered i.m (intramuscular) to rats in the presence or absence of TIR. Testicular weight changes and serum testosterone and total cholesterol levels were evaluated. In addition; the level of testicular tissue reduced glutathione (GSH), malondialdehyde (MDA), total nitrites (NOx) and the activity of superoxide dismutase (SOD) were measured. Histopathology and interleukin1b (IL-1b) immunoexpression were evaluated. KEY FINDINGS: TIR manifested by significant decrease in testicular weight, serum testosterone and testicular tissue GSH levels and SOD activity as well as increase in serum total cholesterol, testicular MDA and NOx levels. TIR showed the histopathological changes of marked testicular damage with increase in IL-1b immunoexpression. DIA was able to normalize both testicular weight, serum testosterone and cholesterol levels with attenuation of oxidative stress parameters along with amelioration of histopathological changes and IL-1 b immunostaining induced by TIR. SIGNIFICANCE: DIA has a protective effect against TIR induced injury in rats mediated by its anti-inflammatory and anti-oxidant activities.

Effect of selective versus non-selective cyclooxygenase inhibitors on ischemia-reperfusion-induced hepatic injury in rats.

AIM: Ischemia-reperfusion (IR) injury represents an important pathological process of liver injury during major hepatic surgery. The role of cyclooxygenase (COX) enzymes in the pathogenesis of ischemia-reperfusion (IR)-induced liver injury is not clear. This study investigated the effect of a selective COX-2 inhibitor, celecoxib, versus non-selective, indomethacin, on hepatic IR injury in rats. MATERIALS AND METHODS: Hepatic IR was induced in adult male rats. The animals were divided into 4 groups: normal control (sham group), IR non-treated group; IR-indomethacin-treated group; and IR-celecoxib-treated group. Liver injury was evaluated by serum alanine aminotransferase (ALT) and a histopathological examination of liver tissues. Hepatic tissue content of oxidative stress parameters glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase, malondialdehyde (MDA), nitric oxide (NO) and the inflammatory marker, tumor necrosis factor-alpha, (TNF-α) were measured. Moreover, the immunohistochemical detection of endothelial NO synthase (eNOS), inducible NO synthase (iNOS), and caspase-3 in the hepatic tissue was performed. KEY FINDINGS: Celecoxib, but not indomethacin, significantly attenuated hepatic IR injury as evidenced by reduction in serum ALT as well as by improvement in the histopathological scoring. Such effect was associated with attenuation in oxidative stress and TNF-α, along with modulation of immunohistochemical expression of eNOS, iNOS and caspase-3 in the hepatic tissue. SIGNIFICANCE: The present study concluded that selective COX-2 inhibition (but not non-selective), is hepatoprotective against liver IR injury; indicating a differential role of COX-1 versus COX-2. Modulation of iNOS, eNOS and caspase-3 might participate in the protective effect of selective COX-2-inhibitors.