Delian Delev

Experimental study on the role of 5-HT2 serotonin receptors in the mechanism of anti-inflammatory and antihyperalgesic action of antidepressant fluoxetine.

ABSTRACT INTRODUCTION: Fluoxetine is an antidepressant that has anti-inflammatory and antihyperalgesic effects in experimental models of pain and inflammation. The AIM of the present study was to determine the role of 5-HT2 receptors in the mechanism of anti-inflammatory and antihyperalgesic action of fluoxetine after single and repeated administration of the drug. MATERIALS AND METHODS: 40 male Wistar rats were randomly divided in five groups (n = 8) treated for 14 days with saline (control), diclofenac (positive control), fluoxetine, cyproheptadine (5-HT2 antagonist), and fluoxetine + cyproheptadine, respectively. We used the experimental model of inflammation induced by intraplantar injection of carrageenan and nociceptive test with mechanical pressure on the inflamed hind paw. RESULTS: Single and repeated administration of fluoxetine showed that it had significant anti-inflammatory and antihyperalgesic effects when compared with the control (p < 0.05). Cyproheptadine did not change significantly the anti-inflammatory effect of fluoxetine in the first 4 hours, after a single administration. At 24 hours the combination did not differ statistically when compared with the control. Cyproheptadin did not change significantly the anti-inflammatory effect of fluoxetine after repeated administration. After prolonged treatment the group that received fluoxetine + cyproheptadine showed a statistically significant increase in paw pressure to withdraw the hind paw compared with that treated with fluoxetine alone (p < 0.05). CONCLUSIONS: Fluoxetine has anti-inflammatory and antihyperalgesic effects in the carrageenan model of inflammation. 5-HT2 receptor mediated its anti-inflammatory effect in single dose treated animals. Spinal 5-HT2 receptors are involved in the antihyperalgesic effect of fluoxetine after repeated administration РЕЗЮМЕ ВВЕДЕНИЕ: Флуоксетин представляет собой антидепресант, обладающий противовоспалительным и антигиперальгезическим эффектами при экспериментальных моделях боли и воспаления. ЦЕЛ: Настоящее исследование ставит себе целью установить роль 5-НТ2 рецепторов в механизме противовоспалительного и антигиперальгезического действий флуоксетина при однократном и многократном применениях. МАТЕРИАЛ И МЕТОДЫ: На 40 мужских крыс породы „Вистар”, разделенных на 5 групп (n = 8), в течение 14 дней воздействовали физиологическим раствором (контрольная группа); диклофенаком (позитивная контрольная группа); флуоксетином, ципрохептадином (5-НТ2 антагонист) и флуоксетином + ципрохептадином. Использованы модель воспаления (интрапланетарноe введениe карагенина) и ноцицептивный тест (механическоe давлениe на воспаленную лапку). РЕЗУЛЬТАТЫ: При однократном и многократном применениях флуоксетина наблюдались сигнификантный противовоспалительныйи антигиперальгезический эффекты - сравнение с контрольной группой (р < 0.05). При однократном воздействии ципрохептадин достоверно не изменяет протививовоспалительный эффект флуоксетина в первые четыре часа, но на 24-ый час комбинация не показывает статистическую разницу при сравнении с контрольной группой. При многократном воздействии ципрохептадин достоверно не изменяет противовоспалительный эффект флуоксетина. Группа крыс, подвергнутая продолжительному воздействию флуоксетином и ципрохептадином, показала сигнификантное увеличение силы давления при отдергивании лапки по сравнению с группой, получившей только флуоксетин (р < 0.05). ВЫВОДЫ: Флуоксетин обладает противовоспалительным и антигиперальгезическим эффектами при карагениновой модели воспаления. 5-НТ2 рецепторы медиируют его противовоспалительный эффект при однократном воздействии. Спинальные 5- НТ2 рецепторы участвуют в реализации антигиперальгезического эффекта флуоксетина при его продолжительном применении

Cerium dioxide nanoparticles possess anti-inflammatory properties in the conditions of the obesity-associated NAFLD in rats

BACKGROUND Obesity is a risk factor for non-alcoholic fatty liver disease (NAFLD). The disease is associated with impairment of pro/antioxidant equilibrium and the inflammation in liver tissue. The aim of the work was to investigate the anti-inflammatory properties of the nanocrystalline cerium dioxide (nCeO2) on the rat model of NAFLD associated with monosodium glutamate (MSG)-induced obesity. METHODS The study was carried out on three groups of rats: control, MSG- and MSG+nCeO2. They were injected with saline (control) or MSG. A month after born MSG-rats had been treated with water in a volume of 2.9ml/kg, MSG+CeO2 groups - with CeO2 intragastrically (i.g.). The anthropometric and carbohydrate metabolism parameters, content of proinflammatory cytokines (interleukin (IL)-1β, IL-12Bp40, interferon-γ (INF-γ)) and anti-inflammatory cytokines (IL-4, IL-10, tumor growth factor-β (TGF-β)) were measured by ELISA. RESULTS We have demonstrated the anti-obesity effect of nanocrystalline cerium dioxide and for the first time its anti-inflammatory properties. Nanoparticles reduced the content of pro-inflammatory cytokines (IL-1β, IL-12Bp40) in rat serum and restored the level of anti-inflammatory cytokines (IL-4, IL-10, TGF-β) to the control values. CONCLUSION The precise mechanisms of this phenomenon remain to be unclear but we suppose they are at least partially associated with the strong anti-oxidant action of studied substance. Nanocrystalline cerium dioxide attenuates the inflammatory processes in rat blood that can prevent obesity complications and liver injury.

Evidence for CD34/SMA positive cells in the left main coronary artery in atherogenesis.

UNLABELLED Regression of atherosclerosis is a key aspect of preventing further coronary artery disease and understanding which cell type forms smooth muscle cells in atherosclerotic fibrous caps will aid in reducing CAD. Atherogenesis is a complex interplay of cells migrating and proliferating into the vascular wall. CD34 positive hemapoetic stem cells are believed to not transform into vascular smooth muscle cells (SMC). The current study hypothesised that there would be no evidence for CD34(+)/α SMC actin(+) cells in atherosclerotic coronary arteries. AIMS To identify CD34+/α actin positive cells in the fibrous cap and wall of atherosclerotic plaques in the coronary artery. METHODS Male New Zealand White rabbits were fed a diet containing 0.5% cholesterol and 1% methionine for 4 weeks, then 9 weeks of normal diet to induce regression. Immunohistochemistry was used to detect CD34(+) haematopoietic progenitor cells and α SMC actin. RESULTS In the fibrous cap, the majority of cells were CD34(-)/α SMC actin(+) spindle shaped cells. However very rare populations of CD34(+)/α SMC actin(+) and CD34(+)/α SMC actin(-) cells were also present but these cells were not spindle shaped. CONCLUSION Our study found that CD34(+)/α SMC actin(-) spindle shaped cells were absent from the fibrous cap. Moreover, the predominant cell population were the vascular smooth muscle cells (CD34(-)/α SMC actin(+)) but (CD34(+)/α SMC actin(+)) cells were also present. This model could be used to understand the role of each SMC population subtype to hasten atherosclerotic regression in the coronary artery.

Quercetin protects jejunal mucosa from experimental intestinal ischemia reperfusion injury by activation of CD68 positive cells

The aim of our study was to analyse the possible protective effect of quercetin application during the jejunal ischemia-reperfusion injury (IRI) in rats. Quercetin was administered intraperitoneally 30min before 1h ischemia of superior mesenteric artery with following 24h lasting reperfusion period. The male specific pathogen-free (SPF) Charles River Wistar rats were used. In the group with applied quercetin, the significantly increased (p<0.001) levels of anti-inflammatory cytokine IL10 were observed both in the blood serum and jejunal tissue. The improvement of the mucosal tissue morphology and proliferating and DNA repairing cell number measured by PCNA activity were recorded by more than 30% higher in the quercetin group. Simultaneously, significant elongation of the intestinal glands (p<0.001) and increase in the number of CD68-positive cells in the lamina propria mucosae (p<0.001) in comparison with control group were found. Based on our results, the preventive application of quercetin before induction of jejunal IRI stimulates faster jejunal mucosa restoration and it seems to have immunomodulatory and anti-inflammatory effects as well. CD68-positive macrophages could have crucial role in this process since they work as both growth factor and cytokine producers.

Effects of polyphenol compounds melanin on NAFLD/NASH prevention

BACKGROUND One of the pathogenic mechanisms of the progression non-alcoholic liver disease (NAFLD) to nonalcoholic steatohepatitis (NASH) is the accumulation of reactive oxygen species (ROS). So, antioxidant therapy is necessary for successful treatment of the liver injury. We have paid attention to melanin produced by yeast Nadsoniella nigra strain X-1 as novel antioxidant and anti-inflammatory agents with low toxicity. In current study we aimed to investigate the preventive effect of melanin on the monosodium glutamate (MSG) induced NAFLD model in rats. METHODS The study was carried out on 45 Wistar rats that were divided into 3 groups: intact, MSG- and MSG+melanin groups (n=15 in each group). Newborn rats of MSG- and MSG+melanin groups were administered with MSG (4mg/g, 8μl/g, subcutaneously) at 2nd-10th days of life. Since the age of 1 month, rats of MSG-group were treated with water (0.25ml/100g), rats of MSG+melanin groups-with melanin (1mg/kg) dissolved in water (0.25ml/100g). INTRODUCTION had been performed intermittently (two-week courses alternated with two-week breaks) for 3 months. In 4-month rats anthropometrical parameters and visceral adipose tissue (VAT) mass were estimated. To assess morphological changes in liver we used NAS (NAFLD activity score). The content of pro-inflammatory cytokines (interleukin (IL)-1β, IL-12Bp40, interferon (INF)-γ) and anti-inflammatory cytokines (IL-4, IL-10, tumor growth factor (TGF)-β) were measured by ELISA. RESULTS We found significantly lower total score (1.0±0.19 vs 3.33±0.36, p<0.001), degree of steatosis (0.73±0.18 vs 1.80±0.17, p<0.001) and manifestation of lobular inflammation (0.27±0.11 vs 1.20±0.17, p<0.001) due to NAFLD activity score in MSG+melanin group compared to MSG-obesity. NASH we confirmed only in 33.3% of rats with MSG-obesity that was significantly higher than after melanin (6.7%) administration (p=0.033). Melanin administration reduce amount of visceral fat on 44.5% (p<0.001) as compared to MSG-obesity group. Melanin reduced the content of IL-1β in rat serum and restored the level of anti-inflammatory cytokines (IL-10, TGF-β) to the control values. CONCLUSION Thus, the administration of melanin can prevent development of NAFLD/NASH in rats with MSG-induced obesity and can be considered as possible novel therapeutic agents but further studies to confirm its action needed.

Effects of novel maleimide derivatives on cell cultures with different properties

The paper is focused on pilot study of effects of novel synthetic protein kinase inhibitors—maleimide derivatives in different concentrations on normal, transformed and multipotent cell lines. Influence on cell proliferation and morphological characteristics has been demonstrated. The chosen agents cause antiproliferative effect on transformed cells and are not cytotoxic to normal cell lines. Moreover, different maleimide derivatives’ effects on multipotent cells in attached and floating states has been shown. Described results can be used for further research of the maleimide derivatives as antitumor agents.

Study on anti-inflammatory and immunomodulatory effects of fluoxetine in rat models of inflammation

The aim of the present study was to evaluate the anti-inflammatory effect of fluoxetine in carrageenan- and lipoplysaccharide-induced models of inflammation by investigating the changes in serum levels of pro-inflammatory cytokine TNF-α and anti-inflammatory cytokines IL-10 and TGF-β after single and repeated administration of the drug. To study the effect of a single and repeated dose fluoxetine on carrageenan-induced paw edema male Wistar rats were divided into five groups (n = 8): control group; positive control group; and three experimental groups treated with 5, 10, and 20 mg/kg bodyweight (bw) fluoxetine, respectively. To study the effect of a single and repeated dose of fluoxetine on serum cytokine levels, the animals were divided in four groups (n = 8): two control groups treated with saline and two experimental groups treated with fluoxetine 20 mg/kg bw. Carrageenan and LPS were injected immediately after fluoxetine or saline injection. Serum cytokine concentrations were tested by enzyme immunoassay. In single administration only the highest dose used inhibited carrageenan-induced inflammation. Edema inhibition was seen with 10 and 20 mg/kg bw fluoxetine after repeated administration. At 24 h a statistically significant effect on inhibition of carrageenan edema was found only in rats treated with 20 mg/kg bw fluoxetine In carrageenan-induced inflammation, fluoxetine significantly increased Il-10 and decreased TNF-α after repeated administration. Surprisingly, in single-dose treated animals an increase in TNF-α values upon fluoxetine administration was observed in this model of inflammation. In LPS-induced inflammation, fluoxetine significantly decreased TNF-α after single and repeated treatment. Fluoxetine has anti-inflammatory and immunomodulatory effect in the carrageenan-induced model of exudative inflammation. In LPS-induced inflammation it showed an immunomodulatory effect manifested with a decrease in pro-inflammatory cytokine TNF-α.

Experimental Study of the Analgesic Effect of the Antidepressant Escitalopram

Abstract Background: Antidepressants have been found to possess antinociceptive and analgesic properties and are prescribed in the treatment of chronic pain. Aim: To evaluate the antinociceptive properties of escitalopram after a single administration. Materials and methods: Forty Wistar rats were used in the study. They were divided into 5 groups (n=8) treated with saline solution (control group), metamizole (150 mg/kg b.w.), escitalopram (5, 10 and 20 mg/kg b.w.) intraperitoneally. The nociceptive tests we used employed thermal (hot plate and plantar test), mechanical (analgesimeter) and chemical (formalin test) stimuli. Criteria for analgesic effect were increased latency in hot plate, plantar test, analgesimeter and decreased paw licking time in formalin test. Results: The reference analgesic metamizole showed significant analgesic effect in all tests excluding the first phase with formalin. Escitalopram in doses of 5 and 20 mg/kg b.w. increased paw withdrawal latency in analgesimeter at 2 hours compared to control. Escitalopram in a dose of 5 mg/kg b.w. increased the duration of the stay on the hot plate at 1 hour, while doses of 10 and 20 mg/kg b.w. significantly increased this indicator at 1 and 3 hours in comparison to the saline treated group. In the plantar test, escitalopram in all used doses significantly increased the nociceptive response latency compared to control. A dose of 5 mg/kg b.w. decreased hind paw licking time during phase 1 of the formalin test, whereas doses of 10 and 20 mg/kg b.w. decreased phase 2 licking time compared to the control group. Conclusion: The antidepressant escitalopram has analgesic properties but they are not dose- or time-dependent.

Changes in Hematologic and Coagulation Profiles in Rabbits with Right-ventricle Pacing

Abstract Objectives: The aim of this study was to evaluate changes in hematology and coagulation in rabbits with right-ventricle pacing without medication. Animals and methods: Blood was collected from ten non-anesthetized male rabbits from the jugular vein before and one month after pacemaker placement. Total erythrocyte, leukocyte and platelet count, hemoglobin, hematocrit and differential leukocyte count were done on automatic veterinary flow cytometry hematologic analyzer. Prothrombin time, activated partial thromboplastin time, fibrinogen level, D-dimers and kaolin-activated thromboelastography was measured from citrated blood. Results: We found an increase in red blood cell mass and decrease in platelet count, while coagulation tests did not diff er between samplings. Conclusion: Right-ventricle pacing seems to have no influence on hemostasis in rabbits.

Effects of Long-Term Treatment with Atorvastatin and Rosuaastatin on Active Avoidance Test in Intact Rats

Summary Statins are widely used for treatment of hyperlipidemia. They have been shown to possess pleiotropic effects apart from their lipid-lowering activity - anti-inflammatory, immunomodulatory, and neuroprotective. Most studies suggest that statins can protect the brain against damage but it is not clear whether they improve cognitive function in patients without neuropathy. The aim of the present study was to investigate the effect of 3-month treatment with atorvastatin and rosuvastatin on learning and memory processes in rats without brain damage. Wistar rats were treated orally for 90 days with atorvastatin and rosuvastatin at a dose of 10 mg/kg b. w. in parallel with the vehicle-treated group. After that period, learning ability and memory retention was evaluated using an active avoidance test - automatic reflex conditioner (shuttle box). The learning session was carried out on 5 consecutive days. Memory retention test was performed on day 12. The following behavioral reactions were investigated: conditioned responses (avoidance), unconditioned responses (escapes), and intertrial crossings. We found increased number of conditioned responses in groups, treated with atorvastatin 10 mg/kg b.w., and with rosuvastatin 10 mg/kg b.w. during the learning session and on the memory retention test, as compared to the same-day control group. The atorvastatin-treated group showed an increased number of unconditioned responses on days 1 and 2, as compared to the control group. In the group treated with Rosuvastatin there was an increased number of escapes on days 1,2 and 4, as compared to the vehicle-treated group. Atorvastatin and rosuvastatin at a dose of 10 mg/kg b.w. improved processes of learning and memory retention after the 3-month treatment.