Soha S. Essawy

Comparing the effects of inorganic nitrate and allopurinol in renovascular complications of metabolic syndrome in rats: role of nitric oxide and uric acid.

Introduction The epidemic of metabolic syndrome is increasing worldwide and correlates with elevation in serum uric acid and marked increase in total fructose intake. Fructose raises uric acid and the latter inhibits nitric oxide bioavailability. We hypothesized that fructose-induced hyperuricemia may have a pathogenic role in metabolic syndrome and treatment of hyperuricemia or increased nitric oxide may improve it. Material and methods Two experiments were performed. Male Sprague-Dawley rats were fed a control diet or a high-fructose diet to induce metabolic syndrome. The latter received either sodium nitrate or allopurinol for 10 weeks starting with the 1st day of fructose to evaluate the preventive role of the drugs or after 4 weeks to evaluate their therapeutic role. Results A high-fructose diet was associated with significant (p < 0.05) hyperuricemia (5.9 ±0.5 mg/dl), hypertension (125.2 ±7.8 mm Hg), dyslipidemia and significant decrease in tissue nitrite (27.4 ±2.01 mmol/l). Insulin resistance, as manifested by HOMAIR (20.6 ±2.2) and QUICKI (0.23 ±0.01) indices, as well as adiposity index (12.9 ±1.1) was also significantly increased (p < 0.1). Sodium nitrate or allopurinol was able to reverse these features significantly (p < 0.05) in the preventive study better than the therapeutic study. Conclusions Fructose may have a major role in the epidemic of metabolic syndrome and obesity due to its ability to raise uric acid. Either sodium nitrate or allopurinol can prevent this pathological condition by different mechanisms of action.

Addition of a low dose of rimonabant to orlistat therapy decreases weight gain and reduces adiposity in dietary obese rats

The aim of the present study was to determine whether the addition of a subeffective dose of rimonabant (1 mg/kg) to orlistat would be beneficial in the treatment of diet‐induced obesity in rats compared with orlistat monotherapy. Male rats were divided into five groups: (i) rats fed a low‐fat diet for 4 months; (ii) rats fed a high‐fat diet (HFD) for 4 months and treated daily with vehicle (0.2% Tween‐80 solution); (iii) orlistat (10 mg/kg per day)‐treated HFD‐fed rats; (iv) rimonabant (1 mg/kg per day)‐treated HFD‐fed rats; and (v) HFD‐fed rats treated with a combination of orlistat plus rimonabant. Fasting blood glucose, serum insulin, leptin and adiponectin levels were measured. Liver and adiposity indices were calculated and liver and adipose tissues were processed for histological examination. Over the 4 months of the study, vehicle‐treated HFD‐fed rats exhibited increased cumulative food intake, bodyweight and liver and adiposity indices. Moreover, vehicle‐treated HFD‐fed rats exhibited a deterioration in liver function and an abnormal lipid profile. Insulin resistance and serum leptin were increased in this group, whereas serum adiponectin levels were decreased. Orlistat monotherapy or combination therapy with orlistat plus rimonabant improved all these parameters. The addition of the low subeffective dose of rimonabant to orlistat therapy ameliorated HFD‐induced obesity to a much greater extent than orlistat monotherapy. This combination showed better weight control and metabolic profile compared with orlistat alone. Therefore, the results of the present study encourage reassessment of the use of a low dose of rimonabant to potentiate the effect of orlistat in the clinical management of obesity if proper clinical safety data are available.

Myelosuppressive and hepatotoxic potential of leflunomide and methotrexate combination in a rat model of rheumatoid arthritis

BACKGROUND Safety of the combination of leflunomide and methotrexate was examined in several studies with inconclusive results. The present study was designed to compare the efficacy and safety of the combination of leflunomide and methotrexate in adjuvant-induced arthritis (AIA) in rats focusing on immunosuppressive and hepatotoxic effects. METHODS Eighty four rats were divided into seven groups. Group 1: Sham control, group 2: the vehicle control, group 3: methotrexate group, group 4-5: leflunomide (5 and 10mg/kg/day) groups, group 6-7: combination 1 and 2 [methotrexate+leflunomide (5 and 10mg/kg/day)] groups, respectively. RESULTS The current results indicated that combination therapies improved the ankle circumference and clinical scores compared to monotherapies; histopathological examination confirmed these findings. The myelosuppressive effect of leflunomide (10mg/kg/day) was comparable to that produced by methotrexate as indicated by the complete blood count and bone marrow cellularity; however their combination resulted in greater toxicity. Furthermore, methotrexate greatly affected the splenic histopathology compared to leflunomide and the combination therapy produced a greater effect compared to leflunomide not methotrexate. Differently, assessment of the hepatotoxic potential of the two drugs highlighted that leflunomide induced a dose-dependent increase in the fibrosis score which was higher in their magnitude than that induced by methotrexate. Leflunomide (10mg/kg/day) and combination 2 groups showed the greatest degree of liver fibrosis. CONCLUSIONS In rats with AIA, current drug combinations provided higher therapeutic benefit compared to monotherapies, however, greater toxicities were observed. Therefore, continuous monitoring of hematologic parameters and liver function will be recommended in clinical settings.

Effects of intravenous human umbilical cord blood CD34+ stem cell therapy versus levodopa in experimentally induced Parkinsonism in mice

Introduction Parkinsonism is a neurodegenerative disease with impaired motor function. The current research was directed to investigate the effect of CD34+ stem cells versus levodopa in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinsonism. Material and methods Mice were divided into 4 groups; saline-injected, MPTP: received four MPTP injections (20 mg/kg, i.p.) at 2 h intervals, MPTP groups treated with levodopa/carbidopa (100/10 mg/kg/twice/day for 28 days) or single intravenous injection of 106 CD34+ stem cells/mouse at day 7 and allowed to survive until the end of week 5. Results Levodopa and stem cells improved MPTP-induced motor deficits; they abolished the difference in stride length, decreased percentage of foot slip errors and increased ambulation, activity factor and mobility duration in parkinsonian mice (p < 0.05). Further, they significantly (p < 0.05) increased striatal dopamine (85.3 ±4.3 and 110.6 ±5.3) and ATP levels (10.6 ±1.1 and 15.5 ±1.14) compared to MPTP (60.1 ±3.9 pmol/g and 3.6 ±0.09 mmol/g, respectively) (p < 0.05). Moreover, mitochondrial DNA from mice treated with levodopa or stem cells was in intact form; average concentration was (52.8 ±3.01 and 107.8 ±8.6) and no appreciable fragmentation of nuclear DNA was found compared to MPTP group. Regarding tyrosine hydroxylase (TH) immunostaining, stem cell group showed a marked increase of percentage of TH-immunopositive neurons (63.55 ±5.2) compared to both MPTP (37.6 ±3.1) and levodopa groups (41.6 ±3.5). Conclusions CD34+ cells ameliorated motor, biochemical and histological deficits in MPTP-parkinsonian mice, these effects were superior to those produced by levodopa that would be promising for the treatment of PD.

The antifibrotic effects of alveolar macrophages 5-HT2C receptors blockade on bleomycin-induced pulmonary fibrosis in rats

BACKGROUND The most widespread chronic fibrosing lung disease is idiopathic pulmonary fibrosis. Lung serotonin (5-HT) content is increased during pulmonary fibrosis with the implication of 5-HT2 receptors in the pathogenesis. Serotonin plays important roles in alveolar macrophages function through 5-HT2C receptors activation. Numerous studies described the important role of 5-HT2A/B receptor blockers in suppressing different types of fibrosis as idiopathic pulmonary fibrosis. The current study pointed to examine the antifibrotic effects of RS-102221 and/or terguride through in vivo model of pulmonary fibrosis. METHODS Induction of pulmonary fibrosis was through a single dose of intra-tracheal bleomycin instillation (5mg/kg dissolved in phosphate buffer saline) in adult male albino Wistar rats. Next day of bleomycin instillation, intraperitoneal injection of RS-102221 (0.5mg/kg/d) and/or terguride (1.2mg/kg/d) were administered and continued for 14 days. RESULTS Noticeable increase in 5-HT2C receptors expression was observed in fibrotic lung tissues with marked allocation belonging to alveolar macrophages. Either RS-102221 or terguride reduced the increments in lung water contents, grading of lung fibrosis, lung tumor necrosis factor-alpha (TNF-α), transforming growth factor-beta1 (TGF-β1) and vascular endothelial growth factor (VEGF) levels in lung injury and fibrosis-induced by bleomycin. Moreover, collagen content and myofibroblasts-alpha smooth muscle actin (α-SМA) were significantly decreased. Additionally, the simultaneous administration of RS-102221 with terguride had a synergistic outcome compared to that obtained by individual monotherapy. CONCLUSION These findings suggested the potential use of 5-HT2A/B/C antagonists as anti-fibrotic agents in lung fibrosis.

Effects of adenosine receptor antagonists in MPTP mouse model of Parkinson’s disease: mitochondrial DNA integrity

Introduction In Parkinson’s disease (PD), compelling data indicate a functional link between adenosine/dopamine receptors and the progression of the neurodegenerative process. The present study was carried out to evaluate the effect of the non-selective adenosine receptor (ADR) antagonist caffeine, as well as the selective antagonists 8-cyclopentyl-1,3-dipropylxanthine (DPCPX), an ADRsA1 antagonist, and ((E)-1,3-diethyl-8-(3,4-dimethoxystyryl)-7-methyl-3,7-dihydro-1H-purine-2,6-dione) (KW-6002), an ADRsA2A antagonist, on the prevention of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinsonism in mice. Material and methods Mice were allocated to five groups: group I – control group; group II: MPTP group, received four injections of MPTP (20 mg/kg, i.p.) at 2 h intervals; groups III, IV, V: received MPTP and i.p. caffeine (20 mg/kg/day) or DPCPX (5 mg/kg/day) or KW-6002 (10 mg/kg/day) starting one week before MPTP injection and continuing for 2 weeks. Results Therapy with caffeine or KW-6002 not only led to the reversibility of movement dysfunction and increased the concentrations of dopamine and ATP levels (p < 0.05), but also, ameliorates the dopaminergic neuron loss and restored the mtDNA and nDNA integrity (p < 0.05). Furthermore, in passive avoidance test, caffeine and DPCPX significantly (p < 0.05) reversed the MPTP-induced memory deficits, whereas the specific ADRsA2A antagonist did not. Conclusions The current results provide evidence that blockade of both ADRsA1 and ADRsA2A has therapeutic implications in alleviating MPTP-induced motor and cognitive dysfunction and might be a promising candidate for treatment of PD.

Effects of intravenous human umbilical cord blood mesenchymal stem cell therapy versus gabapentin in pentylenetetrazole-induced chronic epilepsy in rats.

Aim: The identification and application of stem cells to treat central nervous system disorders represent a dramatic evolution and expansion into the realms of neurorestoration and neuroregeneration. The aim of this study was to assess the possible ameliorative effect of mesenchymal stem cells (MSCs) in comparison to gabapentin on pentylenetetrazole (PTZ)-induced epileptogenesis and its consequences. Methods: Thirty-two rats were divided into 4 equal groups; group I: saline-injected group, group II: PTZ group, which received 13 intraperitoneal (i.p.) injections of PTZ (30 mg/kg) 3 times/week, groups III and IV: groups received PTZ and were treated with i.p. gabapentin (200 mg/kg) 60 min before each PTZ injection (group III) or a single intravenous injection of 106 MSCs/rat at day 22 (group IV). Results: Treatment with either gabapentin or MSCs demonstrated a significant improvement in the PTZ-induced epileptogenesis and its severe consequences, i.e. oxidative stress damage, motor and cognitive impairments. Moreover, they enhanced the GABA neurotransmitter levels. Meanwhile, MSC administration to chronic epileptic rats afforded more ameliorative effects on PTZ-induced epileptogenesis and its severe consequences in comparison to gabapentin. Conclusion: These data indicate that MSCs were superior to gabapentin in ameliorating PTZ-induced epileptogenesis and verified the potential use of MSCs in seizure control, motor and cognitive impairments, oxidative stress, and the impairing GABA level in experimentally induced epilepsy.

Cysteamine Potentiates the Anti-Depressive Effects of Venlafaxine in Corticosterone-Induced Anxiety/Depression Mouse Model: Effect on Brain-Derived Neurotrophic Factor and Tropomyosin-Related Kinase B

The hypothalamic-pituitary-adrenal (HPA) axis abnormalities have been linked to the occurrence of severe depressive and anxiety states. Venlafaxine, a serotonin and a noradrenaline reuptake inhibitor (SNRI), is an approved antidepressant agent with evidence of non-response to treatment in a subset of patients. In this study, 48 male mice (30-38 g) were used to evaluate the possible anxiolytic and antidepressant influence of intraperitoneal (i.p.) cysteamine (150 mg/kg/day) on i.p. venlafaxine (10mg/Kg and 20mg/Kg), as well as effects on brain-derived neurotrophic factor (BDNF) level and tropomyosin-related kinase B (TrkB) gene expression in prefrontal cortex (PFC) in corticosterone-induced anxiety/depression mouse model. The present results provided evidence on insufficient venlafaxine anxiolytic and antidepressant effects in this model. However, cysteamine combined with venlafaxine caused significant antidepressant behavioral effects together with a significant increase in BDNF levels followed by TrkB receptor downregulation in mice PFC. In conclusion, we highlight the potential use of a combination therapy of venlafaxine and cysteamine as a therapeutic strategy for glucocorticoid-related symptoms of depression.

Effect of celecoxib and cisplatin combination on apoptosis and cell proliferation in a mouse model of chemically-induced colonic aberrant crypt foci

Abstract The use of cisplatin for the treatment of cancer is accompanied by dose-dependent adverse effects. In colorectal cancer, there is upregulation of cyclooxygenase-2 (COX-2) expression increases prostaglandin E2 (PGE2) which in turn depresses apoptosis and potentiates invasion, angiogenesis, cell-proliferation and metastasis. This study investigates a possible synergistic function for celecoxib in cisplatin-based chemotherapy against chemically-induced colon carcinogenesis in mice. Mice received fifteen injections of 1,2-dimethylhydrazine dihydrochloride (DMH; 20 mg/kg/week, s.c.) to induce colon carcinogenesis and the normal control group received equal volumes of normal saline. Mice were randomly divided into five groups, (I) normal control group, (II) DMH control group (III) DMH + cisplatin (4 mg/kg/week, i.p.) group, (IV) DMH + celecoxib (10 mg/kg/day by gavage) group and (V) DMH + cisplatin + celecoxib group. Drugs were administered starting from week eleven until the end of the experiment (week 15). Colon specimens were used to evaluate histological grades, examine intratumoral expression of Bcl2, BAX and caspase-3 and the number of proliferating nuclei. The combination of cisplatin and celecoxib was effective against malignant transformation in mice with DMH-induced colonic aberrant crypt foci (ACF). The combination group showed improvement in histological grading, the highest caspase-3 expression and the lowest Bcl2/BAX ratio and reduction by approximately 50% of immunoreactivity for proliferating cell nuclear antigen (PCNA) compared to DMH control group. Addition of celecoxib to cisplatin regimen promotes apoptosis, suppresses tumor proliferation and augments the antitumor effect of cisplatin chemotherapy in the mouse model of DMH-induced ACF.

New insights on the modulatory roles of metformin or alpha-lipoic acid versus their combination in dextran sulfate sodium-induced chronic colitis in rats

BACKGROUND Dextran sulfate sodium (DSS)-induced colitis is the most widely used model that resembles ulcerative colitis (UC) in human with challenging chronic mechanistic oxidative stress-inflammatory/immunological cascades. In models of acute colitis, reduction of oxidative stress and inflammatory burdens beside manipulation of many transcriptional factors were achieved by metformin or alpha-lipoic acid (α-LA). Currently, in vivo DSS-induced chronic colitis was conducted and the possible therapeutic roles of metformin and/or α-LA were explored. METHODS Chronic UC was induced by adding 5% DSS orally in drinking water for 7days followed by 3% DSS in drinking water for 14days in adult male albino Wistar rats. Intraperitoneal administration of α-LA (25mg/kg, twice/day) and/or metformin (100mg/kg/day) were set at day 7 of DSS administration and continued for 14days. Body weights, survival rates, disease activity index (DAI), colonic oxidative stress markers, tumor necrosis factor (TNF)-α levels, colonic nuclear factor-kappa-B (NF-κB) immunohistochemical expression, and the colonic histopathological changes were observed. RESULTS Metformin or/and α-LA attenuated the severity of the DSS-induced colitis through improving the reductions in body weights, the DAI, the colonic oxidative stress markers, TNF-α, and NF-κB levels, and the morphological mucosal damage scores. Significant synergetic therapeutic effects were observed with combined therapeutic regimens. CONCLUSION Therapeutically, metformin and α-LA could be administered in chronic colitis. The combination of currently used pharmaceutics with natural and synthetic potent antioxidant compounds will become a therapeutic strategy of choice for UC to improve the quality of life if sufficient clinical trials are available.