Zekiye Altun

Evaluation of the effect of acetyl L-carnitine on experimental cisplatin nephrotoxicity.

Background/Aims: To evaluate the protective effects of acetyl L-carnitine (ALCAR) on cisplatin-induced nephrotoxicity in rats, and to gain insights into the possible protective mechanisms of ALCAR against nephrotoxicity. Methods: Twenty-eight Wistar rats were divided into four groups. Group 1 was administered saline only, group 2 was administered ALCAR, group 3 was administered cisplatin, and group 4 was administered ALCAR prior to cisplatin. Rats were sacrificed after 72 h of cisplatin/saline infusion. Serum creatinine and glomerular filtration rate values were obtained, and kidney samples were examined by light and electron microscopy. Apoptotic cell death and caspase-3, 8 and 9 activities were studied immunohistochemically. Results: In group 4, ALCAR administration resulted in an improvement in kidney function tests. Histopathological findings confirmed the biochemical data. Whilst the fusion of the foot processes of podocytes was observed in group 3, they were intact in group 4 on electron-microscopic examination. Apoptotic cell death and caspase-3, 8 and 9 activities were also decreased in group 4 compared to group 3. Conclusions: Antioxidative, antiapoptotic and anti-inflammatory properties of ALCAR were supported by the findings that this agent improves kidney function tests and has the effects of tissue protection and inhibition of apoptosis in cisplatin-induced nephrotoxicity.

The anti-oxidant effect of alpha-tocopherol in the prevention of experimentally induced myringosclerosis.

Hypothesis: The objective of this study was to investigate the possible effect of alpha-tocopherol on the prevention of experimentally induced myringosclerosis. Background: Myringosclerosis is a common sequela of ventilation tube treatment of otitis media with effusion. The relationship between oxygen-derived free radicals and occurrence of myringosclerosis has been proven in experimental models, and it was also shown that the formation of myringosclerosis after experimental myringotomy could be reduced by application of various free radical scavengers. Methods: Eighteen Wistar albino rats were myringotomized on the left side and randomly separated into two groups: group A consisted of rats which received intramuscular alpha-tocopherol injections 100 mg/kg daily and group B which were injected with physiological serum only. The occurrence of myringosclerotic plaques in the tympanic membranes of the two groups was compared by otomicroscopy, histopathology, and tympanometry, which is a novel method of quantification. Blood samples were collected for biochemical evaluation, and the tympanic membranes were harvested on the 15th day of the experiment. Results: In otomicroscopic evaluation, tympanic membranes in group B revealed varying degrees of myringosclerotic plaques; on the other hand, tympanic membranes in group A showed faint or no existence of myringosclerosis. The mean malondialdehyde levels were 1.33 ± 0.11 &mgr;mol/L in group A and 7.49 ± 1.37 &mgr;mol/L in group B (Z = −1.906, p = 0.057). In all ears from group B, the magnitude of the maximum admittance measured by tympanometry reduced to approximately 40% of the values obtained from group A (Z = −2,160, p = 0.031). The mean magnitude of the maximum admittance from group A was very close to the standardization values of Wistar albino rats, which predicts a functional outcome. Conclusion: The formation of myringosclerosis after experimental myringotomy can be diminished by intramuscular alpha-tocopherol injections.

Protective effect of acetyl‐l‐carnitine against cisplatin ototoxicity: role of apoptosis‐related genes and pro‐inflammatory cytokines

Cisplatin is an anti‐neoplastic agent treatment with which causes many side effects including ototoxicity. The aim of this study was to investigate whether acetyl‐l‐carnitine would have protective effects on cisplatin‐induced ototoxicity in vitro, and if present, to reveal roles of apoptotic gene expressions and pro‐inflammatory cytokines.

Evaluation of the Effect of Acetyl L-Carnitine on Experimental Cisplatin Ototoxicity and Neurotoxicity

Introduction: Cisplatin (CDDP) is an effective and widely used chemotherapeutic agent for pediatric tumors, and ototoxicity is one of the dose-limiting side effects. Objective: It was the aim of our study to investigate the effect of acetyl L-carnitine (ALCAR) on experimental CDDP ototoxicity by audiologic tests, histomorphologic, immunohistochemical and ultrastructural examinations and to investigate the apoptotic pathways. Materials and Methods: Wistar albino rats (n = 28) were studied. Baseline audiological tests were performed in 4 groups: group 1, control; group 2, ALCAR; group 3, CDDP; group 4, CDDP + ALCAR-administered rats. Control audiological tests were performed on the 3rd day, and then the rats were sacrificed. Ear and brain specimens were examined by transmission electron microscopy, and caspase 3, 8 and 9 activities were investigated. Results: The CDDP-administered rats showed significant auditory brainstem response threshold shifts using all stimuli (clicks, 6-kHz and 8-kHz tone burst) compared with the control groups. The CDDP + ALCAR-administered rats showed significant auditory brainstem response threshold shifts by only click stimuli compared with the control groups. In the brain, spiral ganglion and organ of Corti, ultrastructural damage was prominent in group 3; the number of TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling)-positive cells and caspase 3, 8 and 9 immunostaining cells was significantly high in group 3. Conclusion: ALCAR improves CDDP-induced auditory impairment, and also antioxidative and antiapoptotic properties of ALCAR on CDDP ototoxicity were supported by the findings.

The effects of moderately oxidised dietary oil with or without vitamin E supplementation on performance, nutrient digestibility, some blood traits, lipid peroxidation and antioxidant defence of male broilers

BACKGROUND The experiment was conducted to determine the effects of dietary supplementation of oxidised oil with or without vitamin E on performance, nutrient digestibility, some blood traits, lipid peroxidation and antioxidant defence system of male broilers. RESULTS The supplementation of oxidised oil with or without vitamin E to the grower diets did not significantly affect performance, the pH and viscosity values of excreta and nutrient digestibilities in male broilers. Oxidised oil supplementation slightly increased plasma triglyceride and cholesterol concentrations but did not alter plasma glucose concentration. Although malondialdehyde (MDA) and nitric oxide concentrations tended to be higher in the oxidised oil group, these increases were not significant. Birds fed the diet containing oxidised oil had significantly lower superoxide dismutase (SOD) activity. However, no differences were observed in glutathione peroxidase (GSH-Px) activity and uric acid concentrations of broilers fed oxidised oil as compared to the control group. Dietary vitamin E supplementation decreased MDA concentration whereas increasing SOD activity, suggesting that vitamin E supplementation reduced susceptibility to lipid peroxidation. CONCLUSION The results showed that a milder oxidative stress occurred by supplementation of moderately oxidised oil to the diet of broilers and vitamin E supplementation had been helpful in alleviating lipid peroxidation.

Promoting effects of sanguinarine on apoptotic gene expression in human neuroblastoma cells.

Neuroblastoma is the most common extracranial solid tumor in children. Approximately half of the affected patients are diagnosed with high-risk poor prognosis disease, and novel therapies are needed. Sanguinarine is a benzophenanthridine alkaloid which has anti-microbial, anti-oxidant and anti-inflammatory properties. The aim of this study is whether sanguinarine has in vitro apoptotic effects and which apoptotic genes might be affected in the human neuroblastoma cell lines SH-SY5Y (N-myc negative), Kelly (N-myc positive, ALK positive), and SK- N-BE(2). Cell viability was analysed with WST-1 and apoptotic cell death rates were determined using TUNEL. After RNA isolation and cDNA conversion, expression of 84 custom array genes of apoptosis was determined. Sanguinarine caused cell death in a dose dependent manner in all neuroblastoma cell lines except SK-N-BE(2) with rates of 18% in SH-SY5Y and 21% in Kelly human neuroblastoma cells. Cisplatin caused similar apoptotic cell death rates of 16% in SH-SY5Y and 23% in Kelly cells and sanguinarine-cisplatin combinations caused the same rates (18% and 20%). Sanguinarine treatment did not affect apoptototic gene expression but decreased levels of anti-apoptotic genes NOL3 and BCL2L2 in SH-SY5Y cells. Caspase and TNF related gene expression was affected by the sanguinarine-cisplatin combination in SH-SY5Y cells. The expression of regulation of apoptotic genes were increased with sanguinarine treatment in Kelly cells. From these results, we conclude that sanguinarine is a candidate agent against neuroblastoma.

Friend or foe? Effect of oral resveratrol on cisplatin ototoxicity

Our objectives were to study effects of orally administered resveratrol (RV) against cisplatin (CDDP) ototoxicity in different doses and to investigate ultrastructural changes in the cochlea and brainstem.

Effects of oral L-arginine supplementation on blood pressure and asymmetric dimethylarginine in stress-induced preeclamptic rats

This study was carried out to elucidate the role of asymmetric dimethylarginine (ADMA) and nitric oxide (NO) in preeclampsia development, and to investigate the effect of L‐arginine supplementation in rats. Preeclampsia was induced in pregnant rats using a stress model. L‐arginine was administered orally and ADMA, urinary nitrate, and protein levels were measured on the 20th day of pregnancy. Compared with the group of rats that are normally pregnant, the levels of blood pressure (BP), protein excretion, and ADMA were significantly increased in preeclampsia which returned to normal levels following the supplementation of L‐arginine. Both group of rats had similar urine nitrate levels. Arginine–ADMA–NO pathway is affected in preeclampsia. L‐arginine supplementation decreased hypertension (HT), proteinuria, and ADMA levels indicating that taking L‐arginine may be beneficial in preeclampsia treatment. Copyright

Resveratrol Reduces Matrix Metalloproteinase-2 Activity Induced by Oxygen-Glucose Deprivation and Reoxygenation in Human Cerebral Microvascular Endothelial Cells

The main pathophysiology in cerebral ischemia is the structural alteration in the neurovascular unit, coinciding with neurovascular matrix degradation. Among the human matrix metalloproteinases (MMPs), MMP-2 and -9, known as gelatinases, are the key enzymes for degrading type IV collagen, which is the major component of the basal membrane that surrounds the cerebral blood vessel. In the present study, we investigated the effects of resveratrol on cytotoxicity, reactive oxygen species (ROS), and gelatinases (MMP-2 and -9) in human cerebral microvascular endothelial cells exposed to 6 hours of oxygen-glucose deprivation and a subsequent 24 hours of reoxygenation with glucose (OGD/R), to mimic ischemia/reperfusion in vivo. Lactate dehydrogenase increased significantly, in comparison to that in the normoxia group. ROS was markedly increased in the OGD/R group, compared to normoxia. Correspondingly, ROS was significantly reduced with 50 μM of resveratrol. The proMMP-2 activity in the OGD/R group showed a statistically significant increase from the control cells. Resveratrol preconditioning decreased significantly the proMMP-2 in the cells exposed to OGD/R in comparison to that in the OGD/R group. Our results indicate that resveratrol regulates MMP-2 activity induced by OGD/R via its antioxidant effect, implying a possible mechanism related to the neuroprotective effect of resveratrol.

Effect of Cytotoxic Agents and Retinoic Acid on Myc-N Protein Expression in Neuroblastoma

AimNeuroblastoma is an important pediatric tumor in which Myc-N amplification is a well-known poor prognostic indicator. It has a great diversity in clinical behavior. The effect of pharmacologic agents used in neuroblastoma treatment on Myc-N expression is still unclear. MethodWe analyzed Myc-N expression changes by immunocytochemistry in Myc-N-positive Kelly human neuroblastoma cell line using retinoic acid and cytotoxic drugs (cisplatin, vincristine, cyclophosphamide, etoposide, and doxorubicin) and their combinations compared with control conditions. First, concentration of drugs were determined as LD50 doses. Kelly cells and drugs were incubated for 24 hours in 5% CO2, 37°C in 96-well plates. Myc-N expression was scored semiquantitatively as negative, mild, moderate, or high positive. ResultsMyc-N amplification did not change with any agent or combination. It was higher than 20 copies in all conditions. Myc-N protein expression was high in control and doxorubicin group. It was moderate in retinoic acid, cyclophosphamide, retinoic acid combined with cyclophosphamide and retinoic acid combined with doxorubicin groups. The expression was mild in cisplatin, vincristine, etoposide, retinoic acid combined with etoposide, and retinoic acid combined with cisplatin groups. Myc-N expression was negative in retinoic acid combined with vincristine group. ConclusionsMyc-N expression is reduced with cytotoxic agents and retinoic acid in neuroblastoma although Myc-N amplification remains the same. Retinoic acid combined with vincristine is the most effective combination to reduce Myc-N expression. Our results suggest that therapeutic applications of these agents as low dose maintenance therapy might be useful.