Protection against acute adriamycin-induced cardiotoxicity by nigella sativa oil, thymoquinone, garlic extract and COQ[10] in rats

Oxidative stress is a major etiologic factor in adriamycin [ADR]-induced cardiotoxicity that limits the clinical efficacy of this anticancer drug. Since, many beneficial health-related biological properties are attributed to Nigella sativa L. oil [NSO], thymoquinone [TQ], garlic, and Coenzyme Q-10, the present study examined the cardioprotective effect of these remedies against ADR-induced cardiotoxicity. The study was carried out on 110 male Albino rats. They were divided into a control group [10 rats] and 5 groups of ADR-treated rats [n=20 in each] as follows: [i] ADR, [ii] CoQ10+ADR [iii] NSO+ADR [iv] Garlic+ADR and [v] TQ+ADR groups. Administration of CoQ10, NSO, garlic, and TQ were started one week prior to ADR and continued once daily thereafter for the next 2 weeks. The assessment of cardiac affection was carried out by measuring the level of serum creatine kinase [CK] and lactate dehydrogenase [LDH]. Also, activities of superoxide dismutase [SOD], catalase [CAT], glutathione peroxidase [GPX], cytosolic aconitase [c-aconitase] as well as the malondialdehyde [MDA] and cell iron content were measured in myocardial tissue homogenate. Moreover, light and electron microscopic changes were scored. The administration of ADR to the experimental rats produced wide range of changes. A significant decrease in activities of the antioxidant enzymes SOD, CAT and GPX in ADR-treated rats was found compared to normal control values. Also, myocardial MDA level was significantly high as well as serum LDH and CK denoting myocardial injury. The ADR-treated rats also showed significant inhibition of myocardial c-aconitase activity and rise of cell iron content compared to control myocardium. The histological results of this group revealed hypereosinophilia, myofibrillar damage, nuclear abnormalities, mitochondrial degeneration and diminished glycogen. Neither CoQ10 nor the whole oil of nigella sativa significantly modified ADR-induced impairment in SOD, GPX or CAT activity. CK was significantly less elevated in the NSO but insignificantly different in the CoQ10 while LDH was significantly less elevated in both groups compared to ADR group. Activity of c-aconitase was significantly higher in NSO than CoQ10 and ADR groups while cellular iron was insignificantly different. Also, survival was significantly improved in the NSO but not in the CoQ10 compared to ADR group. These findings were further documented by the histological findings. Examination of ADR-CoQ[10] treated rats showed extensive cellular damage including the mitochondria, intercalated discs, the cytoskeleton, the nuclei and diminished glycogen deposition. Conversely, 3 weeks administration of TQ and garlic in the present study have yielded encouraging results against acute ADR-induced cardiotoxicity in rats, as indicated by 100% survival rate which was found in these groups versus 40-50% in the ADR and CoQ10 treated groups. Moreover, they have been associated with: conserved activity of myocardial antioxidant enzymes GPX, SOD and CAT with suppression of MDA formation and less accumulation of cellular iron compared to ADR, CoQ10 and NSO treated groups. The histological results further proved this results and revealed high degree of myocardial protection in TQ-treated rats and garlic-treated rats respectively where the most examined myocytes were nearly normal. Thymoquinone [TQ] and garlic had shown significant cardioprotective effect much superior to NSO and CoQ10 against ADR-induced myocardial toxicity. The low TQ content in the chosen dose of NSO could be the underlying cause of lacking therapeutic effect although a strong antioxidant effect have been recently reported with this dose of NSO. Hence, a larger dose of NSO and probably of CoQ10 can be subjected to further study for protection against ADR-induced cardiac injury

Effect of folic acid and vitamin B[12] supplementation on isoprenaline induced myocardial infarction, endothelial dysfunction and atherothrombosis in experimental hyperhomocysteinemic rats

Elevated total plasma homocysteine [tHcy] concentration is an independent risk factor for ischemic heart disease and other vascular disorders. Treatment with vitamins [folic acid and B12] has shown to reduce plasma homocysteine level but it is not clear to what extent such treatment may reduce clinical vascular events or mortality. The aim of the present study was to evaluate hyperhomocysteinemia as a risk factor of isoprenaline induced myocardial infarction [MI], endothelial dysfunction and hypercoagulable state and to examine the effect of folic acid either alone or in combination with vitamin B[12] on the experimentally induced myocardial infarction and to evaluate the effect of such vitamin treatment on the biomarkers of endothelial dysfunction and hypercoagulable state in post-methionine load hyperhomocysteinemic rats. Hyperhomocysteinemia [Hhcy] was induced in rats by daily intake of methionine [1g/kg b.wt.] in the drinking water for 4 weeks. MI was then induced by subcutaneous injection of isoprenaline in a dose of 85mg/kg b.wt/day for two days. Serum marker enzymes, creatine kinase [CK] and lactate dehydrogenase [LDH] were measured. Lipid peroxidation was measured as malondialdehyde [MDA] and reduced glutathione [GSH] concentrations in heart tissue. Plasma concentrations of von Willebrand factor [vWF] and D-dimer as markers of endothelial dysfunction and prothrombotic state were measured either in the experimental untreated hyperhomocysteinemic rats or in the treated ones. Hhcy resulted in a significant increase in serum CK and LDH levels. Cardiac MDA was significantly increased while GSH was significantly decreased in Hhcy group compared to the normal control group, plasma concentrations of vWF and D-dimer were also significantly increased. Serum marker enzymes and markers of cardiac oxidative stress were greatly exaggerated in Hhcy rats treated with isoprenaline in comparison with isoprenaline group. Administration of folic acid [10mg/kg, b.wt orally via gavage] alone and in combination with vitamin B[12] [500 ug/kg b.wt. i.m], concurrently for 4 weeks during the induction of Hhcy markedly reduced the increase in serum CK and LDH as well as the plasma concentration of vWF and D-dimer. Cardiac MDA content was decreased while cardiac GSH was elevated in the treated group compared to untreated Hhcy rats. These results suggest that Hhcy aggravates MI via oxidative stress mechanisms and that Hhcy may impair endothelial function and increases the biomarkers of prothrombotic state Treatment with either folic acid alone or in combination with vitamin B[12] can ameliorate the detrimental effects of Hhcy, reduce the risk of MI, appears to improve endothelial dysfunction and decrease plasma concentration of biomarkers of hypercoagulability. This provides preliminary evidence that such vitamin supplementation may have beneficial cardiovascular effects. However clinical benefit of vitamin supplementation has not yet been demonstrated and clinical trials are urgently required

Comparative study of the protective role of Nigella sativa oil, estradiol and alendronate on steroid induced osteoporosis in rats

Corticosteroid [CS] therapy is widely used in the treatment of rheumatic diseases and other inflammatory conditions. This therapy may lead to osteoporosis as one of its major complications. However, in spite of this, prevention of osteoporosis in patients on CS remains low. The pathogenesis of corticosteroid-induced osteoporosis [CIOP] differs from post-menopausal osteoporosis in that bone formation is said to be more suppressed compared with bone resorption. Many agents used in post-menopausal osteoporosis such as, hormone replacement therapy and bisphosphonates have been shown to maintain or improve bone mineral density [BMD]. Moreover, nigella sativa oil [NSO] obtained from nigella sativa L. seeds, the natural herb, is used in many acute as well as chronic diseases. Recently, thymoquinone- an active component of nigella sativa - was shown to enhance bone healing. To assess the comparative effects of NSO, estradiol or alendronate unopposed and in combination with one another for the management of prednisone induced osteoporosis using bone turnover markers. Sixty four adult female albino rats were used in this study. They were classified into eight groups each of eight animals. The first group served as control [received placebo]. The second group received prednisone [1mg/kg b.wt]. The third, the fourth and the fifth group received NSO [800 mg/kg b.wt], estradiol [0.1mg/kg b.wt] and alendronate [0.1mg/kg b.wt] respectively concomitantly with prednisone as in group two. The sixth group received [NSO plus estradiol] as in group 3 and 4. The seventh group received [NSO plus alendronate] as in group 3 and 5. The eighth group received [estradiol plus alendronate] as in group 4 and 5. The animals received placebo and drugs daily orally for six weeks. After six weeks, twenty four hours urine was collected for urinary measurements of hydroxyproline and calcium. The animals were then exposed to light ether anesthesia and blood samples were taken. Serum samples were separated and used for determination of bone specific alkaline phosphates [BSAP], osteocalcin [OC] and calcium. It was found that the use of NSO, estradiol, or alendronate or combination therapy has a protective effect in prednisone induced osteoporosis. NSO significantly decreased urinary hydroxproline and significantly increased serum OC, BSAP and calcium [p<0.05 vs group 2]. Estradiol as well as alendronate significantly decreased urinary hydroxproline [p<0.05vs group 2]. However, alendronate was superior to estradiol [p<0.05]. On the other hand, NSO and estradiol combination showed a marked significant decrease in bone resorption as evidenced by a significant decrease in urinary hydroxyproline [p<0.05vs groups 2, 3]. On the contrary, NSO and alendronate combination caused a significant increase in serum BSAP and OC and a significant decrease in urinary hydroxyproline. [p<0.05vs groups 2, 3 and 5]. Moreover, estradiol and alendronate combination revealed a significant decrease in urinary hydroxyproline [p<0.05vs groups 2, 4, 5, 6 and 7]. Combination therapy with NSO and alendronate is superior to other combinations and to either therapy alone. It decreases bone resorption and increases bone formation more or less near to normal values. Combination therapy may represent an option for women with more severe disease or for those who have failed to achieve an adequate response to monotherapy

study of the cytoprotective effect of clarithromycin on the induced gastric mucosal injury in rats

Clarithromycin, a macrolide antibiotic has been used successfully with antiulcer agents to prolong duodenal ulcer remission and this has been shown to be related to the eradication of Helicobacter pylori. However, it is not well known if clarithromycin possess cytoprotective effects. The aim of the present study was to examine whether clarithromycin may have gastroprotective effect against 96% ethanol-induced gastric lesion in rats and to elucidate the role played by opiate receptors, afferent sensory nerve fibers, alpha and beta-adrenoceptors, endogenous prostaglandins, sulfhydryls, fluid volume and mucous volume retained in the gastric lumen, in the mechanism of protection offered by intragastric clarithromycin against ethanol-induced mucosal injury. Gastric mucosal lesions were induced by 96% ethanol in rats, then the effect of intragastric clarithromycin [50-400 mg/kg b.wt.] on the ethanol-induced lesion was studied. The effect of naloxone [8 mg/kg.b.wt. intraperitoneal], capsaicin [125 mg/kg b. wt. subcutaneous], prazosin [0.5 mg/kg b. wt. subcutaneous], yohimbine [5 mg/kg b. wt. subcutaneous], metoprolol [2 mg/kg b. wt. intraperitoneal], butoxamine [4 mg/kg b. wt. intraperitoneal], indomethacin [5mg/kg b. wt. subcutaneous] and iodoacetamide [100 mg/kg. b.wt. subcutaneous] on the protective effect of clarithromycin was examined. In addition, the effect of clarithromycin on the volume of gastric content was also investigated. Each study was carried out using six rats per group. It has been found that intragastric administration of clarithromycin protected the rat gastric mucosa against 96% ethanol-induced lesion in a dose dependent manner. The inhibition of lesions was 31.86, 51.33, 79.65 and 91.15% at doses of 50, 100, 200 and 400 mg/kg b.wt. respectively. The gastroprotective effect of clarithromycin was not significantly modified by pretreatment with either naloxone; or capsaicin. Subcutaneous pretreatment of rats with prazosin or intraperitoneal pretreatment with metoprolol or butoxamine, did not significantly modify the gastroprotective effect of clarithromycin, However, clarithromycin protection was significantly diminished, although not completely abolished by subcutaneous yohimbine. Clarithromycin protection was not significantly modified by pretreatment with either subcutaneous indomethacin, or iodoacetamide. In addition there was a dose dependent increase in fluid volume and in the mucous volume at 50-400 mg/kg b. wt. of clarithromycin at 30 min. Yohimbine significantly reduced both basal and clarithomycin-stimulated gastric mucous secretion. It could be concluded that the mechanism mediating the intragastric clarithromycin protective effect against 96% ethanol-induced mucosal lesion is independent of opiate receptors, capsaicin-sensitive afferent sensory nerve fibers, alpha[1], beta[1]-, beta[2]-adrenoceptors, endogenous prostaglandins, and sulfhydryl compounds of the gastric mucosa. However, the increase in luminal gastric mucous and fluid volume may contribute to the protective effect of intragastric clarithromycin against 96% ethanol-induced gastric lesion, alpha[2]-adrenoceptos possibly are involved in such protection by a mucous dependent mechanism

Study of the mechanism underlying the prokinetic action of erythromycin on lower esophageal sphincter pressure in dogs

Erythromycin [EM] and a number of its derivatives exhibit prokinetic properties. In particular, the drug increases the contractile activity of smooth muscles of esophagus and promotes gastric emptying in both health and disease. The drug enhances esophageal and gastric motility by acting as a motilin agonist. The aim of the study was to evaluate the effect of low dose of EM, as a prokinetic agent, on the lower esophageal sphincter pressure [LESP] and to study the receptors involved in the mediation of the prokinetic action of EM. The study was carried out on 30 adult healthy dogs [10-15 kg] divided into five groups, each group consisted of 6 dogs. The studied groups were: I: a control group [placebo treated], II: an erythromycin treated group [EM gp] [7 mg/kg b.w. by i.v.i], and three groups III, IV, V that were treated with EM [7 mg/kg b.w. i.v.L preceded by either atropine [a muscarinic blocker] in a dose of 40 micro ag/kg b.w. i.v.i., ondansetrone [5 HT3 antagonist] in a dose of 0.1 mg/kg b.w. i.v.i or metoclopramide [dopamine receptor type 2 antagonist] in a dose of 150 micro g/kg b.w. i.v.i. respectively. After an over night fasting, basal recording of LESP was carried out in each group by an esophageal manometer connected to a pressure transducer. LESP was recorded for all animals in all groups fifteen minutes after the end of the predescribed treatments. Data obtained showed that EM significantly increased the resting LESP. Pretreatment with either atropine or ondansetrone totally prevented the increase in LESP induced by EM. However, pretreatment with metoclopramide failed to prevent the increase in LESP induced by EM. The findings suggest that EM in a low, subantimicrobial dose has a prokinetic action on the lower esophageal sphincter. It was found that this prokinetic action is exerted most probably by stimulating cholinergic pathway and strongly suggested that 5 HT3 receptors are involved in this process. Meanwhile, the dopaminergic receptors seem to have no role in the mediation of this prokinetic action of EM. It is hoped that this prokinetic action of EM could be of a particular benefit in the improvement of GIT motility disorders. However this warrants further investigation to help more understanding of cellular mechanisms regarding that effect of EM

comparative study of the effect of peroxisome proliferator - activated receptor gamma [PPAR - gamma] ligands and angiotensin converting enzyme [ACE] inhibitors on experimental colitis in rats

Peroxisome proliferator - activated receplor-gamma [PPAR- gamma], a member of the nuclear hormone receptor superfamily originally shown to play a critical role in adipocyte differentiation and glucose homeostasis, has recently been implicated as a regulator of cellular proliferation and inflammatory responses. In addition, increasing evidence supports an association between inflammation and angiotensin converting enzyme [ACE]. The aim of this study was to investigate the efficacy of ACE inhibitors [captopril and enalapril] and a PPAR- gamma ligand [rosiglitazone] on acetic acid-induced colitis in rats. Colitis was induced by intracolonic injection of 2 ml of 3% acetic acid. One hundred adult male albino rats were studied in this work. The animals were divided into two main groups, each of fifty rats: group I, of long duration of inflammation and treatment [Three weeks] and group II, of short duration of inflammation and treatment [two days]. Each group was subdivided into five subgroups, each of ten rats namely; control, acetic acid untreated, captopril, enalapril and rosiglitazone-treated rats. The investigated drugs were given two days after induction of colitis and continued daily for three weeks in group I, and for two days before and two days after induction of colitis in group II. Intracolonic injection of acetic acid in rats produced significant inflammation, assessed by the ulcer index score, weight of the colon and the colonic tissue level of myeloperoxidase enzyme in acetic acid untreated rats of both groups. These parameters were significantly improved by administration of captopril, enalapril and rosiglitazone. The effect of rosiglitazone was more potent than captopril and enalapril in both groups. Furthermore, the colonic tissue level of glutathione reductase enzyme was significantly reduced in acetic acid untreated rats of both groups. This reduction was significantly inhibited by the three investigated drugs in both groups, with better results with rosiglitazone than captopril and enalapril - treated rats in both groups. Rosiglitazone, captopril and enalapril also significantly improved the tissue level of lipid peroxides which was significantly elevated in acetic acid - untreated rats of both groups. However, the efficacy of rosiglitazone in reducing the lipid peroxides level was more significant than captopril and enalapril in both groups. this study provides an evidence that the PPAR- gamma ligand, rosiglitazone and the two ACE inhibitors, captopril and enalapril confer a good anti-inflammatory activity against acetic acid-induced colitis in rats. This leads to improvement of oxidative stress induced by the inflammatory insult, with the better results being with rosiglitazone than with captopril and enalapril

Beneficial effects of angiotensin converting enzyme inhibitors captopril and enalapril on experimentally induced colitis in rats

Increasing evidence supports an association between inflammation and angiotensin converting enzyme [ACE]. The aim of this study was to examin the efficacy of ACE inhibitors [ACEIs] namely, captopril and enalapril on acetic acid induced colitis in rats. Colitis was induced by intracolonic injection of 2 ml of 3% acetic acid. Eighty rats were studied in this study, divided into: two main groups, group 1, 40 rats of long duration of inflammation and treatment and group II, 40 rats of short duration of inflammation and treatment. Each group was subdivided into 4 subgroups. 10 control rats, 10 rats injected intracolonic with acetic acid [acetic acid untreated rats], 10 rats injected intracolonic with acetic and plus oral administration of captopril [captopril treated rats], and 10 rats injected intracolonic with acetic acid plus oral administration of enalapril [enalapril treated rats]. Captopril and enalapril were given 2 days after induction of colitis and continued daily for 3 weeks in group I, and for 2 days before and 2 days after induction of colitis in group II. Intracolonic acetic acid injection produced a significant inflammation, assessed by the ulcer index score, the weight of the colon and the colonic tissue level of myeloperoxidase enzyme, in acetic acid untreated rats of both groups. These parameters were significantly improved by ACEIs administration. The effect of captopril in group I was more potent than enalapril, while in group II both ACEIs had the same effect. in group II captopril succeeded to inhibit the change in the weight of the colon or the tissue level of myeloperoxidase enzyme. The colonic tissue level of glutathione reductase was significantly reduced in acetic acid untreated rats of both groups. This reduction was significantly inhibited by ACEIs administration in both groups, with better results with captopril treated rats than enalapril ones in group I. Also the efficacy of captopril in group I was more significant than in group II in improving the glutathione reductase colonic tissue level. Captopril and enalapril also sigificantly improved the level of tissue lipid peroxides, which was significantly elevated in acetic acid untreated rats of both groups. However, the efficiency of captopril in reducing the lipid peroxides level was mor significant than enalapril in both groups. this study provides an evidence that the two ACEIs particularly captopril confers a good anti-inflammatory activity against colitis in rats leading to improvement of oxidative stress induced by the inflammatory insult

study of the effect of H1-and H2-receptor blocking drugs on the normal healing process of excised skin wounds in the rat

In this study, 240 adult healthy albino rats of both sexes were used. They were classified into control and drug-treated groups. Full thickness excised skin wounds were inflicted on the shaved dorsal aspect of the thoracic wall. The mean healing time, rate of wound contraction, the total and the saline soluble collagen concentrations in the healing wound area were measured. Loratadine did not significantly alter any of the wound healing parameters studied. Cimetidine has caused a statistically significant shortening of the mean healing time, acceleration of wound contraction rate, reduction of the total and increase in the saline soluble collagen concentration in the healing wound area 2 and 3 weeks post-wounding