Thymol ameliorates 5-fluorouracil-induced intestinal mucositis: Evidence of down-regulatory effect on TGF-ß/MAPK pathways through NF-κB.

5-Fluorouracil (5-FU) is a front-line cytotoxic therapy. However, intestinal mucositis is a well-known adverse event of 5-FU, which limits its therapeutic use. Indeed, thymol, which is a monoterpene component of the essential oil derived from thymus, has a potential anti-inflammatory and immunomodulatory activity. Therefore, this study aimed to investigate the potential chemoprotective effect of thymol against 5-FU-induced intestinal mucositis. Rats were either exposed to two doses of 5-FU (150 mg/kg, ip) and/or treated with thymol (60 or 120 mg/kg). Oxidative stress and inflammatory markers, as well as pathological changes, were assessed. 5-FU-induced severe intestinal damages as were evidenced by histopathological changes as well as oxidative and inflammatory responses. Thymol pretreatment inhibited 5-FU-induced oxidative stress by reducing lipid peroxidation and increasing intestinal levels of antioxidant systems. Moreover, inflammatory response markers, such as interleukin-6, prostaglandin E2, and COX-2 were also improved. The immunoblotting analysis also showed that thymol significantly inhibited the 5-FU-induced expression of nuclear factor-κB, tumor necrosis factor-α, and transforming growth factor ß-1 (TGF-ß1), in addition to the suppression of p38 and phosphorylated c-Jun N-terminal kinases (p-JNK) mitogen-activated protein kinase proteins' expressions. Our study is the first to demonstrate the promising protective effect of thymol against 5-FU-induced intestinal mucositis through inhibition of oxidative, inflammatory pathways, and suppression of TGF-ß/p38/p-JNK signaling.

Biotin, coenzyme Q10, and their combination ameliorate aluminium chloride-induced Alzheimer's disease via attenuating neuroinflammation and improving brain insulin signaling.

Insulin is important for brain function and neuronal survival. Insulin signaling is initiated by the phosphorylation of insulin receptor substrate-1 (IRS-1) at tyrosine (pTyr) residue. However, IRS-1 is inhibited by phosphorylation at serine (pSer). In Alzheimer's disease (AD), oxidative stress and accumulation of amyloid beta (Aß) induce neuroinflammation, which augments pSer-IRS-1 and reduces pTyr-IRS-1 disturbing insulin signaling pathway. Coenzyme Q10 (CoQ10) and biotin possess antioxidant and anti-inflammatory properties, and, in this study, their impact on insulin signaling is investigated in an aluminium chloride (AlCl3 ) model of AD. AD was induced by oral administration of AlCl3 (75 mg/kg) for 60 days. Biotin (2 mg/kg), CoQ10 (10 mg/kg), and their combination were supplemented concomitantly with AlCl3 for 60 days. Memory test and histological examination were performed. Brain levels of lipid peroxides, antioxidants (reduced glutathione and superoxide dismutase), inflammatory markers (tumor necrosis factor-α, interleukin-6 [IL-6], IL-1, and nuclear factor κB), and phosphorylated Akt (survival kinase) as well as protein levels of Aß, IRS-1 (pTyr and pSer), and caspase-3 (apoptotic marker) were determined. AlCl3 resulted in impaired memory, significant increase in Aß, lipid peroxides, inflammatory markers, caspase-3, and pSer-IRS-1, with significant reduction of the antioxidants, pTyr-IRS-1, and p-Akt reflecting Aß-induced inflammation and defective insulin signaling. Histological examination revealed focal aggregations of inflammatory cells and neuronal degeneration. The biochemical deviations and histological changes were attenuated by the concomitant treatment with biotin and, to greater extent, with CoQ10 and the combination. In conclusion, biotin and CoQ10 could protect against AD via attenuating inflammatory response and enhancing insulin signaling.

Physicochemical and pharmacodynamic evaluation of pioglitazone binary systems with hydrophilic carriers.

Pioglitazone (PGZ) is an antidiabetic agent belongs to thiazolidinediones. Binary systems of PGZ in the matrices of kollicoat IR (KL) and gelucire (GL) at different weight ratios were prepared by kneading and co-evaporation methods, respectively. The drug solid dispersions were characterized in terms of in vitro dissolution studies, differential scanning calorimetry (DSC), and X-ray powder diffraction (XRPD). The effects of PGZ-KL (1:4) solid dispersion on the body weight, blood glucose, renal and hepatic functions of the diabetic rats were evaluated. Enhanced drug dissolution was observed in the case of PGZ-KL binary systems depending on the drug to polymer weight ratio. A reduction of 39.7, 32.7 and 26.6% for diabetic control, PGZ untreated and PGZ-KL (1:4), respectively, was recorded after 2 weeks. PGZ-KL (1:4) solid dispersion also showed significantly lower glucose blood level (p < 0.05) compared to the diabetic control group along the period of experiment. The level of ALT was highly significantly decreased in the animal group treated with PGZ-KL solid dispersion (p < 0.001). However, treatment of diabetic rats with either PGZ-KL or PGZ untreated significantly reduced the level of creatinine compared to the diabetic control and the difference between them was non-significant.

Sitagliptin attenuates myocardial apoptosis via activating LKB-1/AMPK/Akt pathway and suppressing the activity of GSK-3ß and p38α/MAPK in a rat model of diabetic cardiomyopathy.

The present study aimed to investigate the protective effect of sitagliptin, a dipeptidyl peptidase-4 inhibitor, on diabetic cardiomyopathy (DCM)-associated apoptosis and if this effect is mediated via modulating the activity of the survival kinases; AMP-activated protein kinase (AMPK) and Akt & the apoptotic kinases; glycogen synthase kinase-3 ß (GSK-3ß) and p38 mitogen-activated protein kinase (p38MAPK). Diabetes was induced by a single intraperitoneal injection of streptozotocin (55 mg/kg). Diabetic rats were treated with sitagliptin (10 mg/kg/day, p.o.) and metformin (200 mg/kg/day, p.o. as positive control) for six weeks. Chronic hyperglycemia resulted in elevation of serum cardiac biomarkers reflecting cardiac damage which was supported by H&E stain. The mRNA levels of collagen types I and III were augmented reflecting cardiac fibrosis and hypertrophy which was supported by Masson trichome stain and enhanced phosphorylation of p38MAPK. Cardiac protein levels of cleaved casapse-3, BAX were elevated, whereas, the levels of Bcl-2 and p-BAD were reduced indicating cardiac apoptosis which could be attributed to the diabetes-induced reduced phosphorylation of Akt and AMPK with concomitant augmented activation of GSK-3ß and p38MAPK. Protein levels of liver kinase B-1, the upstream kinase of AMPK were also supressed. Sitagliptin administration alleviated the decreased phosphorylation of AMPK and Akt, inactivated the GSK-3ß and p38 AMPK, therefore, attenuating the apoptosis and hypertrophy induced by hyperglycemia in the diabetic heart. In conclusion, sitagliptin exhibits valuable therapeutic potential in the management of DCM by attenuating apoptosis. The underlying mechanism may involve the modulating activity of AMPK, Akt, GSK-3ß and p38MAPK.

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 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.

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.

Date fruits inhibit hepatocyte apoptosis and modulate the expression of hepatocyte growth factor, cytochrome P450 2E1 and heme oxygenase-1 in carbon tetrachloride-induced liver fibrosis.

CONTEXT: Date fruits have protective effects against liver fibrosis; however their anti-apoptotic effects have not been investigated. OBJECTIVE: To investigate the modulating effects of date fruits on pro- and anti-apoptotic markers, cytochrome P450 2E1 (CYP2E1) and hepatocyte growth factor (HGF) in liver fibrosis. MATERIALS AND METHODS: Liver fibrosis was induced by injection of carbon tetrachloride (CCl4) for eight weeks. Date flesh extract (DFE) and pits extract (DPE) were taken daily concomitant with CCl4. Hepatocyte apoptosis was determined by measuring the expression of Fas, caspase-3, Bax, Bcl2 and hemeoxygenase-1 (HO-1). Hepatic levels of HGF and CYP2E1 were determined. RESULTS: Treatment with DFE and DPE significantly attenuated the elevated levels of Fas, caspase 3, Bax and CYP2E1 induced by CCl4. In addition, they alleviated the reduction in Bcl2, HGF and HO-1, the cytoprotective and anti-apoptotic factors in liver. Conclusions DFE and DPE treatment can ameliorate liver fibrosis by inhibiting hepatocyte apoptosis.

The antifibrotic and fibrolytic properties of date fruit extract via modulation of genotoxicity, tissue-inhibitor of metalloproteinases and nuclear factor- kappa B pathway in a rat model of hepatotoxicity.

BACKGROUND: Hepatic fibrosis and its end point; cirrhosis, are the major cause of liver failure and death in patients with chronic liver disease. Therefore, the need for an effective treatment is evident. This study was designed to assess the potential effects of aqueous extract of date fruits, either flesh (DFE) or pits (DPE), on oxidative DNA damage and liver inflammation induced by carbon tetrachloride (CCl4) and whether they are related to inhibition of nuclear factor-κB pathway. In addition, the fibrolytic potential was evaluated via measuring matrix metalloproteinase-9 and tissue inhibitor of metalloproteinases -1 and -2. METHODS: Rats were divided into the following groups: normal control, model control (CCl4 only), CCl4 + DFE, CCl4 + DPE and CCl4 + coffee. Coffee was used as a positive control. Fibrosis was induced by chronic administration of CCl4 (0.4 ml/kg) 3× a week for 8 weeks, and rats were treated with 6 ml/kg/day of DFE or DPE for 8 weeks. Liver homogenate was prepared for evaluation of oxidative stress, DNA damage, inflammatory and fibrolytic markers. Data are analyzed using one-way analysis of variance followed by a Tukey-Kramer post hoc test. RESULTS: Both DFE and DPE significantly attenuated CCl4-induced oxidative damage as indicated by reducing lipid, protein and DNA oxidation in addition to increasing the levels of hepatic catalase activity. Both extracts blocked the accumulation of collagen I in the liver and ameliorated the increased expression of collagen III and α-smooth muscle actin suggesting suppression of profibrotic response induced by CCl4. DFE and DPE also upregulated the expression of heme oxygenase-1 and attenuated the nuclear factor-κB activation and cycloxygenase-2 expression reflecting their anti-inflammatory potential. Additionally, both flesh and pits extracts attenuated the increase in the tissue inhibitor of metalloproteinases -1 and -2 suggesting their fibrolytic activity. CONCLUSION: Our data suggest that DFE or DPE can prevent liver fibrosis by suppressing genotoxicity and nuclear factor-κB inflammatory pathway and by promoting collagen degradation.

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.

Fenofibrate attenuates diabetic nephropathy in experimental diabetic rat's model via suppression of augmented TGF-ß1/Smad3 signaling pathway.

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-ß1 (TGF-ß1) 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-ß1 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-ß1 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-ß1/Smad3 signaling pathway may be a useful therapeutic approach to prevent DN.

Ruboxistaurin attenuates diabetic nephropathy via modulation of TGF-ß1/Smad and GRAP pathways.

OBJECTIVE: To investigate whether ruboxistaurin (a selective PKC-ß inhibitor) mediates renoprotective effect via interference with TGF-ß1/Smad-GRAP cross-signalling. METHOD: Diabetes was induced in rats by a single intraperitoneal injection of streptozotocin (55 mg/kg). Then, the diabetic rats were treated with ruboxistaurin (10 mg/kg, p.o) for 6 weeks. Valsartan (15 mg/kg, p.o) was used as a positive control. After 6 weeks of treatment, diabetic nephropathy biomarkers were assessed. TGF-ß1, Smad2, and Smad3 mRNA and protein levels were detected using qPCR and western blot analysis. KEY FINDINGS: Data showed that serum creatinine, kidney/body weight ratio and urinary albumin excretion significantly increased in diabetic rats. These changes were significantly attenuated by treatment with ruboxistaurin. A significant up-regulation of TGF-ß1, Smad2 and Smad3 mRNA expression was observed in diabetic rats, which was alleviated by administration of ruboxistaurin. Furthermore, immunoblotting showed a significant improvement in protein levels of TGF-ß1 (P < 0.01), Smad2/3 (P < 0.01) and p-Smad3 (P < 0.001) in diabetic rats treated with ruboxistaurin compared to untreated. Importantly, the reduction in GRAP protein expression in diabetic kidney was prevented by treatment with ruboxistaurin. CONCLUSION: These data suggest that the renoprotective effect of ruboxistaurin is possibly due to down-regulation of TGF-ß1/Smad pathway and normalization of GRAP protein expression.

Vitamin D attenuates pro-inflammatory TNF-alfa cytokine expression by inhibiting NF-kB/p65 signaling in hypertrophied rat hearts

A growing body of evidence suggests that immune activation and inflammatory mediators may play a key role in the development and progression of left ventricle (LV) hypertrophy. The present study was designed to test the hypothesis that the cardioprotective effect of cholecalciferol (Vit-D3) is mediated via the regulation of messenger RNA (mRNA) expression of pro-inflammatory cytokines. Rats were randomly divided into four groups: control group received normal saline (0.9 % NaCl) i.p. for 14 days; Vit-D3 group received Vit-D3 at a dose of 12 μg/kg/day by gavage for 14 days; ISO group received saline for 7 days, and at day 7, ISO (5 mg/kg/day) was injected i.p. for 7 consecutive days to induce cardiac hypertrophy; and Vit-D3 + ISO group was treated with Vit-D3 for 14 days, and at day 7, ISO was administered for 7 consecutive days. Heart/body weight ratio, troponin-T, creatine kinase-MB, and tumor necrosis factor-alfa (TNF-alfa) levels of LV tissue were estimated. Levels of mRNA expression of NF-кB (NF-кB)/p65 and inhibitory kappa B (IкB)-alfa were determined by real-time PCR. Vit-D3 administration before and during induction of cardiac hypertrophy significantly reduced (P < 0.001) cardiac biomarkers. The histopathological examination further confirmed these results. In addition, Vit-D3 significantly decreased (P < 0.001) NF-кB-p65mRNA expression and increased (P < 0.01) IкB-alfa mRNA expression in LV tissues compared to ISO group. Based on these findings, it was concluded that the administration of cholecalciferol markedly attenuated the development of ISO-induced cardiac hypertrophy likely through downregulation ofTNF-alfa /NF-кb/p65 signaling pathways. However, it should be pointed out that other signaling pathways may contribute to the cardioprotective effect of Vit-D3 which requires further investigation

Aqueous Date Flesh or Pits Extract Attenuates Liver Fibrosis via Suppression of Hepatic Stellate Cell Activation and Reduction of Inflammatory Cytokines, Transforming Growth Factor- ß 1 and Angiogenic Markers in Carbon Tetrachloride-Intoxicated Rats.

Previous data indicated the protective effect of date fruit extract on oxidative damage in rat liver. However, the hepatoprotective effects via other mechanisms have not been investigated. This study was performed to evaluate the antifibrotic effect of date flesh extract (DFE) or date pits extract (DPE) via inactivation of hepatic stellate cells (HSCs), reducing the levels of inflammatory, fibrotic and angiogenic markers. Coffee was used as reference hepatoprotective agent. Liver fibrosis was induced by injection of CCl4 (0.4 mL/kg) three times weekly for 8 weeks. DFE, DPE (6 mL/kg), coffee (300 mg/kg), and combination of coffee + DFE and coffee + DPE were given to CCl4-intoxicated rats daily for 8 weeks. DFE, DPE, and their combination with coffee attenuated the elevated levels of inflammatory cytokines including tumor necrosis factor-α, interleukin-6, and interleukin-1ß. The increased levels of transforming growth factor-ß1 and collagen deposition in injured liver were alleviated by both extracts. CCl4-induced expression of α-smooth muscle actin was suppressed indicating HSCs inactivation. Increased angiogenesis was ameliorated as revealed by reduced levels and expression of vascular endothelial growth factor and CD31. We concluded that DFE or DPE could protect liver via different mechanisms. The combination of coffee with DFE or DPE may enhance its antifibrotic effects.

Vitamin D attenuates pro-inflammatory TNF-α cytokine expression by inhibiting NF-кB/p65 signaling in hypertrophied rat hearts.

A growing body of evidence suggests that immune activation and inflammatory mediators may play a key role in the development and progression of left ventricle (LV) hypertrophy. The present study was designed to test the hypothesis that the cardioprotective effect of cholecalciferol (Vit-D3) is mediated via the regulation of messenger RNA (mRNA) expression of pro-inflammatory cytokines. Rats were randomly divided into four groups: control group received normal saline (0.9 % NaCl) i.p. for 14 days; Vit-D3 group received Vit-D3 at a dose of 12 µg/kg/day by gavage for 14 days; ISO group received saline for 7 days, and at day 7, ISO (5 mg/kg/day) was injected i.p. for 7 consecutive days to induce cardiac hypertrophy; and Vit-D3 + ISO group was treated with Vit-D3 for 14 days, and at day 7, ISO was administered for 7 consecutive days. Heart/body weight ratio, troponin-T, creatine kinase-MB, and tumor necrosis factor-α (TNF-α) levels of LV tissue were estimated. Levels of mRNA expression of NF-кB (NF-кB)/p65 and inhibitory kappa B (IкB)-α were determined by real-time PCR. Vit-D3 administration before and during induction of cardiac hypertrophy significantly reduced (P < 0.001) cardiac biomarkers. The histopathological examination further confirmed these results. In addition, Vit-D3 significantly decreased (P < 0.001) NF-кB-p65 mRNA expression and increased (P < 0.01) IкB-α mRNA expression in LV tissues compared to ISO group. Based on these findings, it was concluded that the administration of cholecalciferol markedly attenuated the development of ISO-induced cardiac hypertrophy likely through downregulation of TNF-α /NF-кb/p65 signaling pathways. However, it should be pointed out that other signaling pathways may contribute to the cardioprotective effect of Vit-D3 which requires further investigation.

Renoprotective Effects of Fenofibrate via Modulation of LKB1/AMPK mRNA Expression and Endothelial Dysfunction in a Rat Model of Diabetic Nephropathy.

This study was conducted to investigate whether the renoprotective effects of fenofibrate are mediated via attenuation of endothelial dysfunction and modulating the mRNA expression of adenosine monophosphate-activated protein kinase (AMPK) and its downstream kinase liver kinase B1 (LKB1) in rats with diabetic nephropathy (DN). Diabetes was induced by a single intraperitoneal injection of streptozotocin (55 mg kg(-1)). Fenofibrate (100 mg kg(-1), p.o.) was given to diabetic rats daily for 12 weeks. Treatment with fenofibrate significantly improved the renal function as revealed by the significant reductions in urinary albumin excretion and serum levels of creatinine and urea, in addition to the significant increase in creatinine clearance compared with the diabetic control group. Hyperglycemia-induced oxidative damage was ameliorated by treatment with fenofibrate as indicated by the significantly increased levels of glutathione and catalase together with the significant decrease in lipid peroxidation. Administration of fenofibrate caused significant increases in renal nitric oxide (NO) production and mRNA expression of endothelial NO synthase (eNOS), AMPK and LKB1, reflecting improvement of endothelial function. Our results give further insights into the mechanisms underlying the protective role of fenofibrate in DN via modulation of AMPK, LKB1 and eNOS mRNA expression.

Potential impact of silymarin in combination with chlorogenic acid and/or melatonin in combating cardiomyopathy induced by carbon tetrachloride.

The aim of this study was to investigate the effective role of silymarin either alone or in combination with chlorogenic acid and/or melatonin against the toxic impact of carbon tetrachloride (CCl4) induced cardiac infarction. CCl4 (l.2 ml/kg body weight) was administered as a single dose intraperitoneally. The results revealed that the administration of silymarin alone or in combination with chlorogenic acid (CGA) and/or melatonin for 21 consecutive days, 24 h after CCl4 injection to rats, markedly ameliorated the increases in serum markers of cardiac infarction, including troponin T and creatine kinase-MB (CK-MB), as well as increases in the pro-inflammatory biomarkers, including interleukin-6 (IL-6), interferon-γ (IFN-γ) in serum and tumor necrosis factor-α (TNF-α) and C-reactive protein in cardiac tissue compared to CCl4 intoxicated rats. The used agents also successfully modulated the alteration in vascular endothelial growth factor (VEGF) in serum and the oxidative DNA damage and the increase in the apoptosis marker caspase 3 in cardiac tissue in response to CCl4 toxicity. The present biochemical results are supported by histo-pathological examination. The current results proved that treatment with silymarin in combination with CGA and melatonin was the most effective one in ameliorating the toxicity of CCl4 induced cardiac damage and this may support the use of this combination as an effective drug to treat cardiac damage induced by toxic agents.

Adverse cardiac responses to alpha-lipoic acid in a rat-diabetic model: possible mechanisms?

Alpha-lipoic acid (ALA) is widely used as an antioxidant for the treatment of diabetes and its complications; however, the pro-oxidant potential of ALA has recently been reported. This study was designed to investigate whether ALA supplementation could have pro-oxidant effects on cardiac tissues in normal and diabetic rats. Diabetes was induced by a single dose of streptozotocin (STZ; 55 mg/kg (intraperitoneal). Diabetic and normal rats were treated with ALA (100 mg kg−1 day−1) for 45 days. ALA supplementation resulted in oxidative protein damage as evident by significant reduction in the cardiac levels of protein thiol in ALA-treated normal rats (P < 0.01) together with a significant elevation (P < 0.001) in the plasma levels of advanced oxidation protein products in ALA-treated normal rats and in ALA + STZ-diabetic rats compared with the normal control rats. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase has emerged as the major source of superoxide anion and enhanced oxidative damage in heart failure. ALA supplementation increased the myocardial immunoreactivity of p47phox subunit of NADPH oxidase in both normal nondiabetic and diabetic rats reflecting its pro-oxidant effect. Data showed that ALA supplementation failed to prevent cardiac complications in diabetic rats and led to cardiac toxicity in normal rats as indicated by pathological changes (cellular infiltration, fibrosis, and degeneration) and by the elevation of serum cardiac biomarkers compared with normal controls. The pro-oxidant effects of ALA suggest that careful selection of appropriate doses of ALA in reactive oxygen species-related diseases are critical (AU)

Adverse cardiac responses to alpha-lipoic acid in a rat-diabetic model: possible mechanisms?

Alpha-lipoic acid (ALA) is widely used as an antioxidant for the treatment of diabetes and its complications; however, the pro-oxidant potential of ALA has recently been reported. This study was designed to investigate whether ALA supplementation could have pro-oxidant effects on cardiac tissues in normal and diabetic rats. Diabetes was induced by a single dose of streptozotocin (STZ; 55 mg/kg (intraperitoneal). Diabetic and normal rats were treated with ALA (100 mg kg(-1) day(-1)) for 45 days. ALA supplementation resulted in oxidative protein damage as evident by significant reduction in the cardiac levels of protein thiol in ALA-treated normal rats (P < 0.01) together with a significant elevation (P < 0.001) in the plasma levels of advanced oxidation protein products in ALA-treated normal rats and in ALA + STZ-diabetic rats compared with the normal control rats. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase has emerged as the major source of superoxide anion and enhanced oxidative damage in heart failure. ALA supplementation increased the myocardial immunoreactivity of p47phox subunit of NADPH oxidase in both normal nondiabetic and diabetic rats reflecting its pro-oxidant effect. Data showed that ALA supplementation failed to prevent cardiac complications in diabetic rats and led to cardiac toxicity in normal rats as indicated by pathological changes (cellular infiltration, fibrosis, and degeneration) and by the elevation of serum cardiac biomarkers compared with normal controls. The pro-oxidant effects of ALA suggest that careful selection of appropriate doses of ALA in reactive oxygen species-related diseases are critical.

Preventive effects of selenium yeast, chromium picolinate, zinc sulfate and their combination on oxidative stress, inflammation, impaired angiogenesis and atherogenesis in myocardial infarction in rats.

PURPOSE: Accumulating evidences suggest a critical role of trace metal dyshemostasis in oxidative stress and cardiac dysfunction after myocardial infarction (MI). This study investigated the cardioprotective effects of selenium yeast (Se), chromium picolinate Cr(pic)3, zinc sulfate (Zn) and their combination on isoproterenol (ISO)-induced MI. METHODS: Rats were divided into six groups: normal control, ISO control, Se-pretreated (0.1 mg/kg), Cr(pic)3-pretreated (400 µg/kg), Zn-pretreated (30 mg/kg) and metal combination-pretreated groups. All metals were administered for 28 days and at the 27th day, MI was induced by subcutaneous injection of ISO (85 mg/kg) once for two consecutive days. RESULTS: ISO control group showed hyperlipidemia, elevation of cardiac biomarkers and lipid peroxidation and increased immunostaining of p47 phox NADPH oxidase subunit in addition to decreased levels of glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx). Cardiac levels of tumor necrosis factor-α (TNF-α) were increased, while vascular endothelial growth factor (VEGF, the major angiogenic factor) was decreased. Pretreatment with Se normalized the cardiac enzymes, lipid peroxidation, GSH, SOD, CAT, GPx, TNF-α and VEGF (P<0.001) and reduced the immunostaining of p47 phox subunit. However, Se failed to correct the dyslipidemia. Cr(pic)3 significantly improved lipid profile (P<0.001) and all other biochemical deviations except for VEGF. Zn, but to lesser extent, reduced the oxidative damage and TNF-α levels and improved both dyslipidemia and angiogenesis. Combination therapy exhibited less prominent protection compared to individual metals. CONCLUSION: Daily supplementation with trace metals is promising for improving myocardial performance via preventing oxidative damage, induction of angiogenesis, anti-inflammatory and/or anti-hyperlipidemic mechanisms.