Velibor Vasovic

Antioxidant properties of fullerenol C60(OH)24 in rat kidneys, testes, and lungs treated with doxorubicin

Clinical use of doxorubicin continues to be challenged by its undesirable systematic toxicity, caused mainly by oxidative stress. The aim of this study was to investigate the effectiveness of fullerenol C60(OH)24 polyanion nanoparticles, an antioxidant agent, against doxorubicin-induced nephro-, testicular, and pulmonary toxicity. Results obtained in vitro suggest that fullerenol’s anti-proliferative property and protective effect against doxorubicin cytotoxicity are mediated by the antioxidative and radical scavenging activity. Male Wistar rats were divided into five treatment groups: the control group (I) received 0.9% NaCl (1 mL/kg, i.p.). Groups II, III, IV, and V received a single dose of doxorubicin (10 mg/kg i.p.), doxorubicin/fullerenol (100 and 50 mg/kg i.p. of fullerenol 30 min prior to 10 mg/kg i.p. of doxorubicin), and fullerenol (100 mg/kg i.p.), respectively. On the 2nd and 14th days, organ samples were taken for the measurement of lipid peroxidation and activities of superoxide dismutase, catalase, glutathione-peroxidase, -reductase, and -transferase. Doxorubicin induced a significant increase of lipid peroxidation and alterations of antioxidant enzyme activities, while the fullerenol pre-treatment prevented the effects of doxorubicin on investigated parameters. Fullerenol, applied alone, did not alter basal values of the investigated animals. Considering the mechanisms of doxorubicin toxicity, it can be concluded that fullerenol exerts its protective role by acting as a free radical sponge and/or by removing free iron through formation of fullerenol-iron complex. Results of this study support the hypothesis of testicular, pulmo-, and nephroprotective efficacy of fullerenol in preventing oxidative stress induced by doxorubicin.

The Protective Effects of Silymarin against Doxorubicin-Induced Cardiotoxicity and Hepatotoxicity in Rats

Silymarin is a complex of five major compounds, and silibinin is the most biologically active component of the complex. The aim of this study was to investigate, evaluate and confirm the potential cardioprotective and hepatoprotective effects of administration of silymarin, rich in silibinin, at a dose of 60 mg/kg orally for a time-span of 12 days on doxorubicin induced toxicity in male Wistar rats. The in vivo model was used to explore whether silymarin could prevent damage of liver and heart tissue induced by doxorubicin administered every other day at dose of 1.66 mg/kg intraperitoneally for twelve days. In the study the change of body weight, ECG changes, biochemical parameters of oxidative stress, serum activity of alanine and aspartate transaminase, lactate dehydrogenase, creatine kinase and histological preparations of heart and liver samples of treated animals were examined. According to physiological, pharmacological, microscopic and biochemical results, we confirmed that at the examined dose, silymarin exhibits a protective influence on the heart and liver tissue against toxicity induced by doxorubicin.

Effect of stevioside and sodium salt of monoketocholic acid on glycemia in normoglycemic and diabetic rats

SummaryThis study investigated the effect of a commercial preparation of stevioside and a synthetic compound, sodium salt of monketocholic acid (MKC), administered per os (p.o.) and also adminstered via an osmotic pump, on glycemia in normoglycemic and diabetic Wistar rats. Diabetes was induced with alloxan, 100 mg/kg, i.p. Normoglycemic and diabetic rats were treated p.o. for five days either with physiological solution (1 ml/kg, controls), stevioside (20 mg/kg), MKC (4 mg/kg) and a combination of stevioside (20 mg/kg) and MKC (4 mg/kg). Apart from p.o. adminstration, stevioside and MKC were also administered via a subcutaneously (s.c.) implanted osmotic pump. During treatment and upon termination of the latter, glycemia was measured and the rats that were treated p.o. were subjected to the oral glucose tolerance test (OGTT) at a dose of 1 g/kg. Following this animals were anesthetized with urethane (0.75 g/kg, i.p.) and killed by cardiopunction to determine C-peptide levels in the serum. In all three groups of normoglycemic rats highest decrease in glucose levels was observed on the fourth day of the experiment. The stevioside + MKC combination showed a stronger hypoglycemic effect compared to individual treatments with stevioside and MKC (3.73:4.80:4.73 mmol/L). In the group of diabetic rats that received both substances via the osmotic pump, the hypoglycemic action was also stronger compared to the individual treatments with stevioside and MKC (16.15:18.89:18.75 mmol/L). The treatment of healthy rats with both substances p.o. caused no statistically significant difference in glycemia, whereas in diabetic rats the combination of stevioside + MKC showed a statistically significant decrease in glycemia compared to control values. In both groups of rats, treatment with stevioside and MKC and their combination prevented an increase in glucose concentrations in the OGTT. Only the administration of stevioside by osmotic pump yielded a statistically significant increase in the concentrations of C-peptide in the serum of healthy rats. Compared to controls, the concentrations of C-peptide in diabetic rats were significantly higher after treatment with either stevioside or its combination with MKC, irrespective of the mode of administration.

Deoxycholic Acid as a Modifier of the Permeation of Gliclazide through the Blood Brain Barrier of a Rat

Major problem for diabetic patients represents damage of blood vessels and the oxidative stress of the brain cells due to increased concentration of free radicals and poor nutrition of brain cells. Gliclazide has antioxidative properties and poor blood brain barrier (BBB) penetration. Bile acids are known for their hypoglycemic effect and as promoters of drug penetration across biological membranes. Accordingly, the aim of this study is to investigate whether the bile acid (deoxycholic acid) can change the permeation of gliclazide, through the blood brain barrier of a rat model type-1 diabetes. Twenty-four male Wistar rats were randomly allocated to four groups, of which, two were given alloxan intraperitoneally (100 mg/kg) to induce diabetes. One diabetic group and one healthy group were given a bolus gliclazide intra-arterially (20 mg/kg), while the other two groups apart from gliclazide got deoxycholic acid (4 mg/kg) subcutaneously. Blood samples were collected 30, 60, 150, and 240 seconds after dose, brain tissues were immediately excised and blood glucose and gliclazide concentrations were measured. Penetration of gliclazide in groups without deoxycholic acid pretreatment was increased in diabetic animals compared to healthy animals. Also in both, the healthy and diabetic animals, deoxycholic acid increased the permeation of gliclazide through that in BBB.

Effect of rat pretreatment with aqueous solutions of stevioside and bile acids on the action of certain cardioactive drugs

SummaryThe interaction of aqueous solutions of stevioside and bile acids with cardioactive drugs was studied in rats by registering changes in their electrocardiograms (ECG). Wistar rats of both sexes received daily doses of 20 mg/kg (i.p.) of an aqueous solution of stevioside or physiological solution (controls), then were narcotized with urethane and connected to the ECG apparatus for the first recording. The jugular vein was prepared and connected to an infusion pump to administer one of the drugs: adrenaline (0.1 mg/ml), verapamil (2.5 mg/ml) or metoprolol (1 mg/ml) to rats in both groups, while recording their ECGs. In the second part of the study, the animals were treated in the same way but instead of the stevioside solution received a single dose of 4 mg/kg of monoketocholic acid methyl ester (ME) or sodium salt of the same bile acid (MKHNa), 30 minutes before cardioactive drug infusion. The infusion rate of cardioactive drugs was 0.2 ml/min, except for verapamil (0.1 ml/min). The events observed on ECG recordings were the first myocardial reaction to drug infusion, the second longer-lasting reaction (observed as more extended extrasystoles, decrease in intensity of the QRS complex, or changes in heart rate frequency), and toxicity effect. In the control animals, adrenaline induced a decrease in heart rate frequency at a dose of 0.094 mg/kg, while with stevioside-pretreated rats this effect appeared significantly earlier (at a dose of 0.018 mg/kg). No toxic effect of adrenaline was observed, either in control or stevioside-pretreated group. Bile acids caused no changes in myocardial reaction to adrenaline. Only in the group of animals that received MKHNa, a significant decrease in the QRS complex was observed. Finally, the infusion of stevioside to intact animals at doses of 45 and 55 mg/kg caused no significant changes in the ECG patterns. The myocardial reaction to metoprolol remained unchanged in rats of all groups when compared with controls except for a mild decrease in heart rate frequency. Stevioside inducedproduced a significant increase in myocardial sensitivity to verapamil, but no toxic effect was observed in any of the cases. A similar conclusion also holds for the interaction with MKHNa, whereas ME caused an increase in the toxicity of verapamil.

Diclofenac and ketoprofen liver toxicity in rat

SummaryIn the last years there appeared many articles about the adverse influence of non-steroidal anti-inflammatory drugs on the liver and heart. This study is concerned with the influence of the duration of treatment with diclofenac and ketoprofen on the macroscopic and microscopic changes in the liver, lungs, heart, and kidneys in rats. Experiments were carried out on mature Wistar strain rats. Animals of test groups received diclofenac and ketoprofen in a dose of 8 mg/kg/day (equivalent to the therapeutic dose for man) during 7 per os (p.o.) or 28 days intraperitoneally (i.p.), whereas controls received physiological solution p.o. A high morbidity was observed in the animals receiving diclofenac p.o. and somewhat lower in those treated with ketoprofen. On the other hand, the rats got through the 28-day i.p. treatment with both drugs mainly without significant complications. Macroscopic examinations revealed some changes in treated rats: distension of the stomach, ascites, fibrin deposits on the internal organs, lung effusion and the changes in color and structure of the liver. These changes were more frequent in the group of rats receiving diclofenac for the 7 days compared with those that received ketoprofen for the same time. It may be thought that the high mortality and macroscopic changes in the internal organs of experimental animals are a consequence of the microscopic changes in the liver and its lowered function.

Protective effects of orally applied fullerenol nano particles in rats after a single dose of doxorubicin

Polyhydroxylated, water soluble, fullerenol C60(OH)24 nano particles (FNP) in vitro and in vivo models, showed an expressive biological activity. The goal of this work was to investigate the potential protective effects of orally applied FNP on rats after a single dose of doxorubicin (DOX) (8 mg/kg (i.p.)) 6 h after the last application of FNP. After the last drug administration, the rats were sacrificed, and the blood and tissues were taken for the analysis. Biochemical and pathological results obtained in this study indicate that fullerenol (FNP), in H2O:DMSO (80:20, w/w) solution given orally in final doses of 10, 14.4, and 21.2 mg/kg three days successively, has the protective (hepatoprotective and nephroprotective) effect against doxorubicin-induced cytotoxicity via its antioxidant properties.

Effect of caffeine on quinidine transport to the central nervous system in rats.

We studied the effect of caffeine on the transport of quinidine through the blood-brain barrier (BBB) to the central nervous system (CNS) in rats. The anesthetized animals received quinidine in the form of a retrograde intra-arterial bolus injection (15 s) into the right axillary artery 30 min after receiving a subcutaneous injection of caffeine (test group) or physiological solution (control group). Rats were decapitated at 30, 60, 90, 120, and 240 s after quinidine administration. Blood samples were taken from the left jugular vein. Upon washing, the brain, was divided into the brainstem, cerebellum, and cerebral hemispheres to determine the quinidine content in each section, using a standard spectrofluorimetric method. Quninidine attained maximal concentrations in the CNS with a latency compared with that in blood; the CNS values were higher. Quinidine kinetics showed two compartments in the CNS, one consisting of the brainstem and cerebellum, in which quinidine concentrations were higher, and the other the cerebral hemispheres. Caffeine caused a significant deceleration of quinidine transition through the BBB to the CNS.

Interaction of diclofenac and ketoprofen with cardioactive drugs in rats.

SummaryThe interaction of diclofenac and ketoprofen, both applied intraperitoneally in a dose of 8 mg/kg for twenty-eight days, was assessed with cardioactive drugs in rats. Interaction was assessed on the basis of ECG records after the infusion of adrenaline, verapamil or lidocaine to the rats treated with diclofenac or ketoprofen vs control. The infusion time was measured in seconds to the moment of the appearance of the first heart reaction to the infusion of the cardioactive drug, then to the appearance of more frequent changes in the ECG record, and finally, to the occurrence of the toxic effect. It was also measured the plasma concentrations of sodium and potassium ions. As well as diclofenac and ketoprofen concentration, 2 hours after single and 28th dose. ECG patterns revealed no occurrence of cardiotoxic action of diclofenac and ketoprofen. The treatment with diclofenac caused significantly lower sodium plasma concentrations whereas the concentration of potassium was increased. Diclofenac concentrations were the same after a single and multiple doses, whereas concentrations of ketoprofen were significantly higher after a single dose than after its multiple applications.

Effect of aminophylline on aspirin penetration into the central nervous system in rats.

SummaryThis study investigated with the effect of aminophylline on the penetration of aspirin through the blood-brain barrier (BBB) into the central nervous system (CNS) in rats. Acetylsalycylic was injected into the right axillary artery, to avoid the drug affecting the peripheral organs before it reached the CNS. The test animals received subcutaneously (s. c. ) aminophylline 30 min before aspirin injection, while the control animals received an equimolar dose of physiological solution s. c. At time intervals of 30, 60, 90, 120, and 240 s after aspirin injection, the animals were decapitated and blood samples from the left jugular vein, as well as samples from the brainstem, cerebellum and left and right cerebral hemispheres, were taken to determine aspirin concentrations in all of them by a standard method. It was found that aspirin concentrations in the CNS were even 30 times lower than in the blood, with the concentrations being higher in the brainstem and cerebellum than in the left and right hemispheres. The presence of aminophylline did not alter aspirin concentrations either in the blood or the brain, and therefore did not affect significantly the aspirin penetration through the BBB into the CNS.