Omnyah A. El-Kharashi

Fenofibrate A peroxisome proliferator activated receptor-α agonist treatment ameliorates Concanavalin A-induced hepatitis in rats.

Peroxisome proliferator-activated receptor-α (PPARα) is physiologically highly expressed by hepatocytes, where it plays a pivotal anti-inflammatory and metabolic role. The decrease expression and functional activity of PPARα in hepatocytes during hepatitis C virus infection may contribute to the pathogenesis of the disease in humans. This study aims at evaluating the effects of PPARα activation with fenofibrate (FF) on liver inflammation, fibrosis and portal pressure (PP) in Concanavalin A (Con A)- induced hepatitis in rats. The rats were randomly divided to 3 groups; control (1 ml saline iv/wk) group, Con A (20mg/kg/iv/wk) group and Con A with FF (100mg/kg/day p.o) group. Blood samples and livers were collected by the end of the first, second, fourth and eighth injections of Con A for biochemical, histopathological and immunohistochemistry studies for α-smooth muscle actin (α SMA). Measurement of PP was performed by the end of the 8th week. FF group had a significant (P<0.05) decrease of serum alanine and aspartate aminotransferases with significant reduction of hepatic tumor necrosis factor alpha and malondialdehyde levels than Con A group. Histopathological examination revealed that treatment with FF significantly suppressed early inflammation, reduced α SMA, and apoptosis of hepatocytes induced by Con A, thereby preventing the progression of chronic liver injury and fibrosis. In addition FF group had a significantly lower PP (-89.0%) than Con A group. In conclusion PPARα activation significantly reduced liver inflammation, fibrosis and PP in Con A model of hepatitis that may represent a new therapeutic strategy for hepatitis and its complications.

Potential involvement of PPAR α activation in diminishing the hepatoprotective effect of fenofibrate in NAFLD: Accuracy of non- invasive panel in determining the stage of liver fibrosis in rats.

BACKGROUND Although Fenofibrate (FF) is a hypolipedmic drug and one of the PPARα agonists which is a drug target for non alcoholic liver disease (NAFLD), no studies had investigated its potential hepatic effects in such cases. AIM To compare between the effect of FF and Gemfibrozil (GF) on the prognosis of NAFLD in rats. METHODS Sixty four rats were used and classified into two main groups. Group I (treated for 6 weeks): naïve, FF, GF groups and Group II (treated for 14 weeks and drugs were added at the last 6 weeks): Control, high fat diet (HFD) untreated, HFD+FF, HFD+FF+folic acid (FA) and HFD+GF groups. Body weight (BW), liver index (LI), renal perfusion test (RPT), glomerular filtration rate (GFR), serum creatinine (S.cr), plasma homocysteine (Hcy), liver function, non invasive markers of fibrosis and histopathology were done. RESULTS HFD produced significant increase (P<0.05) in BW, LI, S.cr, plasma Hcy, lipid profile and liver enzymes. It showed significant (P<0.05) decrease in GFR and RPT. These findings were correlated to the histopathology. FF through its effect on GFR and renal function induced significant increase in plasma Hcy and that decreased its effectiveness in managing NAFLD associated with hyperlipidemia. The addition of FA improved significantly its hypolipidemic and hepatotoxic effects.GF showed none of the above FF effects and this may be due to its low affinity to PPAR α. CONCLUSIONS There is preference of adding FA to FF or using GF instead in cases of NAFLD. Moreover, this work implies the enhanced liver fibrosis (ELF) panel diagnostic performance in diagnosis of any and moderate degree of fibrosis in rats with NAFLD.

Potential involvement of JNK1 repression in the hepatic effect of sitagliptin and metformin in rats subjected to high fat diet and chronic mild distress

BACKGROUND Depression and non-alcoholic steatohepatitis (NASH) are highly co-morbid, and hepatic JNK pathway may be involved in their relation. AIM To evaluate the impact of depression on NASH through the involvement of JNK1 and to assess the effect of sitagliptin and metformin on hepatic JNK1 expression in both NASH and NASH associated with depression. METHODS Eight groups of male Wistar rats were used: naïve rats, non-stressed NASH, non-stressed NASH sitagliptin treated, non-stressed NASH metformin treated, stressed, stressed NASH untreated, stressed NASH sitagliptin treated and stressed NASH metformin treated. Behavioral, biochemical, molecular and histopathological studies were performed. RESULTS Non-stressed NASH group showed depressive like symptoms, disturbed glucose homeostasis, impairment of liver functions, decrease adiponectin and increase malondialdehyde, which were aggreviated by stress. Sitagliptin produced significant improvement compared to metformin regarding biochemical and histopathological parameters. Furthermore, sitagliptin significantly decreased expression of hepatic JNK1 in both stressed and non-stressed rats. All these changes were accompanied by significant improvement of behavioral changes. CONCLUSIONS The link between NASH and depression raised the role of JNK activation through increase expression of JNK1. Since sitagliptin was associated with preferable effects than metformin, therefore, it is potentially preferred in the management of either NASH or NASH associated with depression.

Potential Renoprotective Effects of Eplerenone and Captopril in L-Name-Treated Rats

In this study, we examined the renoprotective effects of curative and prophylactic doses of eplerenone and captopril in L-NAME-treated rats. Rats were divided into seven groups: The first and second (normal control and hypertensive control) groups received distilled water and L-NAME (L-nitro arginine methyl ester, 50 mg/kg per day), respectively, for eight weeks. The third and fourth groups received L-NAME (50 mg/kg per day) plus a prophylactic dose of eplerenone (50 mg/kg per day) or captopril (25 mg/kg per day), respectively, for eight weeks. The fifth, sixth and seventh groups received L-NAME (50 mg/kg per day) for eight weeks, followed by curative doses of eplerenone (100 mg/kg per day), captopril (50 mg/kg per day) or eplerenone plus captopril (50 + 25 mg/kg per day), respectively, for five weeks. The drugs were administered by gastric gavage. During prophylactic therapy, eplerenone and captopril decreased the L-NAME-induced rise in systolic blood pressure (SBP) and serum creatinine levels. Furthermore, both drugs improved microalbuminuria and renal histopathological changes and increased serum nitric oxide (sNO) levels. During curative therapy, eplerenone improved microalbuminuria and renal histopathological changes. Captopril or the combination of captopril and eplerenone improved all L-NAME-induced changes. The combination improved renal histopathological changes more significantly than each individual drug did. In conclusion, eplerenone and captopril have prophylactic and curative renoprotective effects in L-NAMEtreated rats, indicating the promising role of eplerenone as an add-on therapy to captopril in antihypertensive drug regimens.

Metformin potentiates cognitive and antidepressant effects of fluoxetine in rats exposed to chronic restraint stress and high fat diet: potential involvement of hippocampal c-Jun repression

Several hypotheses link high fat diet (HFD) with the pathophysiology of depression and its response to antidepressants. This study aimed to determine the effect of metformin (MET) on the cognitive and antidepressant activity of fluoxetine (FLU) through its effect on c-Jun expression. Behavioral, cognitive function, biochemical, and histopathological studies were performed in non-HFD- and HFD-fed rats exposed to chronic restraint stress (CRS). Stressed group showed cognitive impairment, depressive-like symptoms, disturbed glucose homeostasis and lipid profile, reduced adiponectin level, brain-derived neurotrophic factor (BDNF) expression, and increased corticosterone and c-Jun. All these were aggravated by HFD. MET, FLU and their combination produced significant improvement in lipid profile with significant increase in adiponectin and BDNF expression. Corticosterone, body weight and insulin resistance showed significant decrease in the treated groups. Moreover, there was a significant decrease in hippocampal c Jun expression. There was a significant preferable effect toward the combination. Conclusion, MET may decrease the refractoriness to FLU and improves the cognition in individuals who are fed on HFD.

Targeting HMGB1/TLR4 axis and miR-21 by rosuvastatin: role in alleviating cholestatic liver injury in a rat model of bile duct ligation

Many pathways are involved in the association between biliary obstruction and liver injury. We investigated the intervention influence and effect of rosuvastatin (Rvs) on the high mobility group protein 1 (HMGB1)/toll-like receptor-4 (TLR4) axis and microRNA-21 (miR-21) in cholestatic liver injury. This model was performed by ligating common bile duct of Wistar rats. Saline and Rvs were orally administrated by gastric gavages. Liver and blood samples were collected and subjected to molecular and biochemical evaluation. We found that the daily oral administration of Rvs was protective against the occurrence of cholestatic liver injury. This was evident from the results of hepatic, oxidative stress, and inflammatory biomarkers. This study also revealed the Rvs inhibitory effect on the HMGB1/TLR4 intracellular signaling axis as evidenced by decreasing the levels of nuclear factor κβ (NFκβ), tumor necrosis factor α (TNFα), and interleukin 6 (IL6) production. Furthermore, Rvs-treated group showed a significant reduction in the expression of miR-21 in comparison to the untreated group. Accordingly, rosuvastatin interference with the HMGB1/TLR4 and miR-21 expression could explain its hepatoprotective effect in cholestatic liver injury.

The protective effect of pentoxifylline versus silymarin on the pancreas through increasing adenosine by CD39 in a rat model of liver cirrhosis: Pharmacological, biochemical and histological study

Impaired glucose homoeostasis due to insulin resistance and decrease sensitivity of pancreatic β-cells is a feature of liver disease and results into hepatogenous diabetes. Decrease expression of CD39 was linked to inflammation and occurrence of diabetes. Therefore, we performed this study to explore the protective effect of pentoxifylline (PTX) and silymarin administration on the β-cells of the pancreas in a rat model of thioacetamide induced liver cirrhosis. Biochemical, histological and immunohistochemistry studies of the liver and pancreas were performed and provided an evidence on the protective effect of PTX to pancreatic β-cells compared to silymarin. Also, silymarin induced a significant improvement of liver cirrhosis compared to PTX. In conclusion, the potential protective effect of PTX against β-cells deterioration could be attributed to increasing pancreatic CD39 expression and the subsequent increase of adenosine.

Insights into hepatic and renal FXR/DDAH-1/eNOS pathway and its role in the potential benefit of rosuvastatin and silymarin in hepatic nephropathy

OBJECTIVES The repression of renal Farnesoid X Receptor (FXR) had been shown to result from lack of bile acid production from cirrhotic liver. We hypothesized that silymarin and rosuvastatin (Rvs) could have a hepatorenal therapeutic effects in hepatic nephropathy through induction of FXR. METHODS Forty two male Wistar rats were used; naïve (n = 12); six of them were sacrificed after 4 weeks and six continued till the end of the experiment. Thirty rats were treated as follows: Rvs, silymarin, thioacetamide (TAA), TAA + Rvs and TAA + silymarin. Liver and kidney function tests as well as the renal and hepatic expression of transforming growth factor β1 (TGFβ1), FXR, dimethylarginine dimethylaminohydrolase-1 (DDAH-1) and eNOS were performed. Histological and immuno-histochemical studies of liver and kidney were also done. RESULTS TAA-inducted liver cirrhosis was associated with significant deterioration of liver and renal functions together with increasing expression of hepatic and renal TGFβ1 and decreasing expression of hepatic and renal FXR, DDAH-1 and eNOS. Giving silymarin or Rvs induced hepatic and renal improvement which was evidenced biochemically and histologically. Significant positive correlation was detected between all the investigated biomarkers except for the correlation between FXR and TGFβ1 which was negative. CONCLUSIONS In conclusion, liver cirrhosis is associated with deterioration of renal functions. Silymarin and Rvs have a potential hepatorenal therapeutic benefit through simultaneous enhancement of FXR/DDAH-1/eNOS pathway in both organs.

Effect of atorvastatin on phenytoin-induced osteoporosis in adult albino rats: a pharmacological and light and electron microscopic study

Introduction Phenytoin, an antiepileptic drug (AED), might affect bone structure and mineralization. Epileptic patients who take AEDs are at increased risk for falls and fractures. Therefore, there is a need for a new approach to increase bone health in these patients. Aim of the work This study was conducted to assess the efficacy of statins in preventing bone loss associated with AEDs. Materials and methods Thirty male adult albino rats were divided into five equal groups. The animals, which received daily treatment by gastric gavage for 5 weeks, were classified into: group I (the control group); group II, in which the rats were given phenytoin 20 mg/kg bw; group III, in which rats received phenytoin as in group II with atorvastatin 5 mg/kg bw; group IV, in which rats were given phenytoin along with atorvastatin 10 mg/kg bw; and group V, in which they were given phenytoin along with atorvastatin 20 mg/kg bw. Biochemical assays, assessment of bone mineral density, light (LM) and scanning electron microscopic studies (SME), as well as morphometric and statistical studies were carried out. Results The present work demonstrated that atorvastatin in a dose-dependent manner significantly (P<0.001) prevented the decrease in serum and bone calcium and phosphorus and bone-specific alkaline phosphatase due to phenytoin administration. There was also a graded improvement in osteocalcin (a marker for osteoblastic activity) and TRAP (a marker for osteoclastic activity) levels. Moreover, atorvastatin significantly inhibited the loss in bone weight, volume, and density. On LM and SEM examination, atorvastatin showed a gradual improvement of the tibia bone with higher doses as there was a significant increase (P<0.05) in trabecular and cortical bone thickness and a significant decrease (P<0.05) in osteoclast numbers per area of bone surface in the metaphysis; compared with the phenytoin-only-treated group, an improvement was seen in the growth of the epiphyseal plate. Conclusion Atorvastatin could be considered a beneficial drug for treatment of osteoporosis in epileptic patients on phenytoin.

Diazepam dose-dependently Aggravates Mucosal Damage in a Rat Model of Ulcerative Colitis

BACKGROUND: Psychiatric co-morbidities, such as anxiety, are common in patients with chronic gut disorders, including those with overt inflammatory conditions of the gastrointestinal tract. Among the available pharmacological options, anxiolytics such as benzodiazepines (BZDs) are considered to be effective drugs; however, no sufficient data are available about their direct effect on gut mucosal impairment. OBJECTIVES: The present work was designed to examine the effect of different doses of diazepam on a rat model of ulcerative colitis. METHODS: Three doses of diazepam were assessed comparatively in an experimental model of ulcerative colitis. Thirty six male albino rats were divided into 5 groups, each consisting of 6 animals; Group I: Sham operated group, Group II: ulcerative colitis was induced with 1 ml 5 % acetic acid by intracolonic instillation without treatment. Groups III, IV&V: diazepam 1, 3 or 6 mg/kg respectively, was administered i.p. for two days with and after inducing ulcerative colitis. Group VI: Vehicle treated group received polyethylene glycol i.p. Distal colon segment was evaluated both macroscopically and microscopically for the degree of damage. The inflammatory response was assessed by measurement of colonic myeloperoxidase activity (MPO), serum tumor necrosis factor (TNF)-α, as well as fecal lactoferrin and calprotectin levels. RESULTS: Rats with induced colitis showed macroscopic & microscopic signs of inflammation; this was associated with a significant increase in TNF-α, MPO as well as fecal lactoferrin and calprotectin contents. In a dose-dependent manner, diazepam administration, at the 3 dose levels, exacerbated the damage produced by acetic acid, this was revealed by gross inspection, as well as histologically and biochemically. CONCLUSIONS: Accordingly, the current study displayed that diazepam has deleterious effects when administrated to colitic rats.