Iman H. Hasan

Sitagliptin attenuates cardiomyopathy by modulating the JAK/STAT signaling pathway in experimental diabetic rats

Sitagliptin, a dipeptidyl peptidase-4 inhibitor, has been reported to promote cardioprotection in diabetic hearts by limiting hyperglycemia and hyperlipidemia. However, little is known about the involvement of the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway modulation in the cardioprotective effects of sitagliptin. The current study aimed to investigate the protective effects of sitagliptin against diabetic cardiomyopathy (DCM), focusing on the modulation of the JAK/STAT pathway. Diabetes was induced by streptozotocin injection, and rats received sitagliptin orally and daily for 90 days. Diabetic rats exhibited hyperglycemia, hyperlipidemia, and a significant increase in heart-to-body weight (HW/BW) ratio. Serum troponin I and creatine kinase MB, cardiac interleukin-6 (IL-6), lipid peroxidation, and nitric oxide levels showed significant increase in diabetic rats. In contrast, both enzymatic and nonenzymatic antioxidant defenses were significantly declined in the heart of diabetic rats. Histopathological study revealed degenerations, increased collagen deposition in the heart of diabetic rats. Sitagliptin alleviated hyperglycemia, hyperlipidemia, HW/BW ratio, histological architecture, oxidative stress, and inflammation, and rejuvenated the antioxidant defenses. In addition, cardiac levels of pJAK2 and pSTAT3 were increased in diabetic rats, an effect which was remarkably decreased after sitagliptin treatment. In conclusion, these results confer an evidence that sitagliptin has great therapeutic potential on DCM through down-regulation of the JAK/STAT signaling pathway.

Simvastatin prevents isoproterenol-induced cardiac hypertrophy through modulation of the JAK/STAT pathway.

Simvastatin (SIM) is a lipid-soluble inhibitor of hydroxy-3-methylglutaryl coenzyme A reductase with multiple reported therapeutic benefits. The present study was designed to investigate the effect of pretreatment with SIM on isoproterenol (ISO)-induced cardiac hypertrophy in rats. Twenty-four male albino Wistar rats weighing 180–200 g were divided into four groups. Groups I and III received normal saline while groups II and IV received SIM (10 mg/kg body weight) for 30 days per gavage. In the last 7 days, rats of groups III and IV were administered ISO (5 mg/kg) intraperitoneally to induce cardiac hypertrophy. Administration of ISO induced an increase in heart-to-body weight (HW/BW) ratio, an increase in serum interleukin-6, and elevated systolic and diastolic blood pressure. Serum levels of lipids, cardiovascular risk indices, and cardiac troponin I and creatine phosphokinase-MB showed significant increase in ISO-induced hypertrophic rats. Histopathological examination of heart tissue revealed focal areas of subendocardium degeneration, mononuclear cellular infiltrations, fibrous tissue deposition, and increased thickness of the myocardium of left ventricle. In addition, ISO-administered rats exhibited significant upregulation of cardiac Janus kinase, phosphorylated signal transducer and activator of transcription, and nuclear factor-kappa B. Pretreatment with SIM significantly prevented ISO-induced cardiac hypertrophy, alleviated the altered biochemical parameters, and improved the heart architecture. In conclusion, our study provides evidence that SIM prevented the development of cardiac hypertrophy via modulation of the Janus kinase/signal transducer and activator of transcription-signaling pathway in the heart of ISO-administered animals.

Fenofibrate attenuates diabetic nephropathy in experimental diabetic rat's model via suppression of augmented TGF-β1/Smad3 signaling pathway

Abstract Context: Fibrates, the ligands of peroxisome profileferator-activated receptor-α have been shown to have a renal protective action in diabetic nephropathy (DN). Objective: This study aimed to elucidate the effect of fenofibrate on renal transforming growth factor-β1 (TGF-β1) and Smad3 in Streptozotocin (STZ)-induced DN. Methods: Diabetes was induced in rats by a single intraperitoneal injection of streptozotocin (55 mg/kg). Diabetic rats were given fenofibrate (100 mg/kg, p.o.). After 12 weeks, diabetic nephropathy biomarkers were assessed. The mRNA expression of collage I and III, TGF-β1 and Smad3 and were detected by RT–PCR. Results: Fenofibrate reduced significantly serum creatinine, kidney/body weight ratio, serum albumin excretion Collage I & III, TGF-β1 and Smad3 mRNA expression. Conclusions: Our results give further insights into the mechanisms underlying the protective role of fenofibrate in DN, suggesting that interference with TGF-β1/Smad3 signaling pathway may be a useful therapeutic approach to prevent DN.

Simvastatin Ameliorates Diabetic Cardiomyopathy by Attenuating Oxidative Stress and Inflammation in Rats

Simvastatin is a lipid-lowering agent used to treat hypercholesterolemia and to reduce the risk of heart disease. This study scrutinized the beneficial effects of simvastatin on experimental diabetic cardiomyopathy (DCM), pointing to the role of hyperglycemia-induced oxidative stress and inflammation. Diabetes was induced by intraperitoneal injection of streptozotocin and both control and diabetic rats received simvastatin for 90 days. Diabetic rats showed significant cardiac hypertrophy, body weight loss, hyperglycemia, and hyperlipidemia. Serum creatine kinase MB (CK-MB) and troponin I showed a significant increase in diabetic rats. Simvastatin significantly improved body weight, attenuated hyperglycemia and hyperlipidemia, and ameliorated CK-MB and troponin I. Simvastatin prevented histological alterations and deposition of collagen in the heart of diabetic animals. Lipid peroxidation and nitric oxide were increased in the heart of diabetic rats whereas antioxidant defenses were decreased. These alterations were significantly reversed by simvastatin. In addition, simvastatin decreased serum inflammatory mediators and expression of NF-κB in the diabetic heart. Cardiac caspase-3 was increased in the diabetic heart and decreased following treatment with simvastatin. In conclusion, our results suggest that simvastatin alleviates DCM by attenuating hyperglycemia/hyperlipidemia-induced oxidative stress, inflammation, and apoptosis.

Protective effects of silymarin, alone or in combination with chlorogenic acid and/or melatonin, against carbon tetrachloride-induced hepatotoxicity

Objective: The aim of this study was to evaluate the hepatoprotective effects of silymarin (SIL), alone and combined with chlorogenic acid (CA) and/or melatonin (ME), using a rat model of carbon tetrachloride (CCl4)-induced injury. Materials and Methods: Hepatotoxicity was induced by a single dose of CCl4 (1 ml/kg, IP). One day after, rats were received SIL (200 mg/kg) alone or in combination with CA (60 mg/kg) and/or ME (20 mg/kg) for 21 days. Results: SIL significantly decreased serum alanine aminotransferase, inflammatory cytokines, and vascular endothelial growth factor levels. Histological alterations, fibrogenesis, oxidative DNA damage, inflammatory mediators, and caspase-3 activity were significantly attenuated in SIL treated CCl4-intoxicated rats. On the other hand, cytochrome P450 2E1 activity showed a significant decrease in the liver of CCl4-intoxicated rats, an effect that was reversed following treatment with SIL. All beneficial effects of SIL were markedly potentiated when combined with CA and/or ME. Conclusions: These data indicate that SIL, alone and combined with CA and/or ME, protected the liver against CCl4-induced hepatotoxicity via attenuating inflammation, oxidative DNA damage, apoptosis, and fibrotic changes. The significantly intensified hepatoprotective effects of SIL when combined with both CA and ME suggest a possible synergism. These synergistic effects need to be further confirmed using detailed studies.

Simvastatin ameliorates diabetic nephropathy by attenuating oxidative stress and apoptosis in a rat model of streptozotocin-induced type 1 diabetes

Statins are HMG-CoA reductase inhibitors with lipid-lowering effect and commonly used to reduce cardiovascular risk in diabetic patients. The present study investigates the ameliorative effect of simvastatin (SIM) on diabetic nephropathy in rats, pointing to its anti-apoptotic and anti-oxidative stress efficacies. Diabetes was induced by a single intraperitoneal injection of 55 mg/kg body weight streptozotocin (STZ) and both control and diabetic rats received 10 mg/kg SIM for 90 days. Treatment with SIM diminished the body weight loss, blood glucose and, serum creatinine, urea and uric acid in diabetic rats. SIM improved the creatinine clearance rate and urinary levels of creatinine, urea and albumin in STZ-induced rats. Lipid peroxidation and nitric oxide (NO) were significantly increased in the diabetic kidney whereas reduced glutathione, SOD and catalase were declined. Bax and caspase-3 showed a significant increase and Bcl-2 was decreased in the kidney of diabetic rats. SIM administration reduced lipid peroxidation and NO, and improved antioxidants and the expression of apoptotic markers. Diabetic rats showed increased collagen deposition in the kidney, atrophied irregular renal corpuscles with collapsed glomeruli and tubules with degenerated epithelial lining, an effect that was reversed following treatment with SIM. In conclusion, SIM can protect against diabetic nephropathy by attenuating oxidative stress and apoptosis.

Possible involvement of the JAK/STAT signaling pathway in N-acetylcysteine-mediated antidepressant-like effects

Advances in depression research have targeted inflammation and oxidative stress to develop novel types of treatment. The JAK/STAT signaling pathway plays pivotal roles in immune and inflammatory responses. The present study was designed to investigate the effects of N-acetylcysteine, a putative precursor of the antioxidant glutathione, in an animal model of depression, with an emphasis on the JAK/STAT signaling pathway. Fluoxetine, a classical antidepressant drug was also under investigation. Male Wistar rats were subjected to forced swimming test and given N-acetylcysteine and fluoxetine immediately after the pre-test session, 5 h later and 1 h before the test session of the forced swimming test. N-acetylcysteine decreased immobility time (P < 0.05), serum corticosterone (P < 0.001), and hydrogen peroxide (P < 0.001), while restored glutathione concentration. Treatment of the rats with N-acetylcysteine produced significant (P < 0.001) down-regulation of STAT3 mRNA expression and protein phosphorylation. On the other hand, N-acetylcysteine significantly (P < 0.001) increased SOCS3 gene expression; however, SOCS3 protein was not changed. In conclusion, our study suggests that modulation of the JAK/STAT pathway might mediate the antidepressant-like effects of N-acetylcysteine. Therefore, depression research may target the JAK/STAT signaling pathway to provide a novel effective therapy.

Possible protective mechanisms exerted by metformin or metformin and vitamin E in isoproterenol-induced cardiac injury

Several studies have reported that metformin is cardioprotective for diabetic and non‐diabetic ischemic hearts through mechanisms that cannot be entirely attributed to its anti‐hyperglycemic effect. This study was designed to investigate the cardioprotective effects of metformin with and without vitamin E after induction myocardial infarction (MI) in rats, using isoproterenol. Administration of metformin or vitamin E significantly reduced the cardiac mass index (P < 0.01), ameliorated the changes to cardiac biomarkers, and attenuated oxidative stress levels compared to the isoproterenol group. Interestingly, combination therapy showed a slight synergistic effect. Histopathological analysis suggested that metformin treatment reduced NF‐κB expression and protected against isoproterenol‐induced MI. Our results indicate that metformin mediates a cardioprotective effect against isoproterenol‐induced MI via antioxidant activity and modulation of the NF‐κB signaling pathway. This suggests that metformin would be beneficial in MI treatment.

Role of Some Natural Antioxidants in the Modulation of Some Proteins Expressions against Sodium Fluoride-Induced Renal Injury

Background The aim of the present work is to find the effects of N-acetylcysteine (NAC) and/or thymoquinone (THQ) in the protection against acute renal injury induced by sodium fluoride (NaF). Method Rats were distributed into five groups: G1 was normal (control), G2 was intoxicated with 10mg/kg NaF i.p., G3 was treated with 10mg THQ /kg, G4 was treated with 20mg NAC /kg, and G5 was treated with a combination of THQ and NAC. The previous treatments were given daily along with NaF for four weeks orally. Result Rats intoxicated with NaF showed a significant increase in serum urea, creatinine, uric acid, renal lipid peroxidation, nitric oxide, and TNF-α levels, whereas the activity of superoxide dismutase (SOD) and glutathione (GSH) level was reduced. The expressions of Toll-like receptor-4 (TLR4), Lipocalin, vascular adhesion molecule-1(VCAM-1), and BAX proteins were upregulated, whereas Bcl-2 and NF-E2-related factor 2 (Nrf2) proteins expressions were downregulated. DNA fragmentation was also amplified. Histological analysis revealed that NaF caused a destructive renal cortex in the form of the glomerular corpuscle, the obliterated proximal and distal convoluted tubules, vacuolization in tubular cells focal necrosis, and cell infiltration. THQ and NAC supplementation counteracted NaF-induced nephrotoxicity as reflected by the increase in renal GSH and SOD. THQ and NAC ameliorated all the altered proteins expressions, improved renal architecture, and declined DNA fragmentation. Conclusion The role of oxidative stress in the enhancement of NaF toxicity suggested the renoprotective effects of NAC and THQ against the toxicity of fluoride via multiple mechanisms.

Amelioration of panadol-induced nephrotoxicity via down-regulation of Bax/Bcl2 ratio with some antioxidants

BACKGROUND Overdoses of Panadol (APAP) result in hepatic and renal toxicity. Up till now, there is no effective drug for APAP-enhanced nephrotoxicity. This work aims to explore the protective effects of N-acetylcysteine, Thymoquinone (THQ), Curcumin (CUR) and α-Lipoic acid (LA) either alone or in combination against APAP nephrotoxicity, focused on modulation of Bax/Bcl2 pathway. METHODS APAP was administrated at a single dose then treated with the fore mentioned antioxidants. RESULTS APAP administration increased serum creatinine, urea, uric acid, tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β) levels compared to control group. There is a marked depletion of reduced glutathione (GSH) levels and superoxide dismutase activity (SOD), Bax level was overexpressed, whereas Bcl2 was downregulated in renal tissue. Histopathological examination of the kidney tissue supported these biochemical findings. Treatment with the fore mentioned anti-oxidants ameliorated most of the previous evaluated parameters and returned the kidney nearly to its normal architecture. CONCLUSION The expression of Bax and Bcl2 is considered one of the mechanisms underlying APAP-induced nephrotoxicity. The administration of THQ along with CUR could be a promising antidote for APAP renal damage through their antioxidant potential.