Subchronic toxicity of Sideritis scardica, Lamiaceae on male Wistar rats.

INTRODUCTION: Sideritisscardica, Lamiaceae, is a plant with anti-inflammatory, antirheumatic, digestive, and antimicrobial properties that is widely used in folk medicine throughout the Balkan Peninsula. The name derives from the Greek word 'sideros', meaning iron, and it is believed that the plant was also used by soldiers to heal wounds caused by cutting weapons.

Cisplatin treatment reduces contraction to angiotensin II by altering expression of angiotensin II receptors: a pilot study.

The renin angiotensin system is a key regulator of blood pressure homeostasis. Angiotensin type 1 (AT1R) and 2 receptors (AT2R) have been investigated as targets for cisplatin-induced acute kidney injury; however, their therapeutic potential remains inconclusive. This pilot study aimed to determined the effect that acute cisplatin treatment had on angiotensin II (AngII)-induced contraction in blood vessels and expression profiles of AT1R and AT2R in mouse arteries and kidneys. Male C57BL/6 mice at 18 week of age (n = 8) were treated with vehicle or bolus dose of cisplatin (12.5 mg/kg). Thoracic aorta (TA), adnominal aorta (AA), brachiocephalic arteries (BC), iliac arteries (IL) and kidneys were collected for isometric tension and immunohistochemistry analysis. Cisplatin treatment reduced IL contraction to AngII at all doses (p < 0.01, p < 0.001, p < 0.0001); however, AngII did not induce contraction in TA, AA or BC in either treatment group. Following cisplatin treatment, AT1R expression was significantly upregulated in the media of TA (p < 0.0001) and AA (p < 0.0001), and in the endothelium (p < 0.05) media (p < 0.0001) and adventitia (p < 0.01) of IL. Cisplatin treatment significantly reduced AT2R expression in the endothelium (p < 0.05) and media (p < 0.05) of TA. In renal tubules, both AT1R (p < 0.01) and AT2R (p < 0.05) were increased following cisplatin treatment. Herein, we report that cisplatin reduces AngII-mediated contraction in IL and may be explained by an absence of normal counterregulatory expression of AT1R and AT2R, indicating other factors are involved.

Cannabidiol improves memory and decreases IL-1ß serum levels in rats with lipopolysaccharide-induced inflammation.

AIM: Memory improving and anti-inflammatory properties of cannabidiol (CBD) were investigated in an experimental model of lipopolysaccharide (LPS)-induced inflammation.

Analysis of biometric parameters of 2340 eyes measured with optical biometer Lenstar LS900 in a Caucasian population.

OBJECTIVES: To describe the pattern and mutual relationships between basic biometric characteristics of the eye in a Central European Caucasian population. METHODS: A single-centre retrospective study of 2340 patients (965 males, 1375 females) scheduled for cataract surgery between 2014 and 2016. Measurements using laser interferometry included AL (axial length), K (average corneal curvature), ACD (anterior chamber depth), LT (lens thickness), CCT (central corneal thickness), AST (astigmatism) and WTW (white to white). Subjects were stratified by gender and controlled for age. Descriptive, correlation and regression analyses were performed on the data. RESULTS: The mean AL was 23.33 ± 1.01 mm - higher in males (23.59 ± 0.99 mm), in comparison to females (23.15 ± 0.99 mm). The elderly had lower ACD and higher LT, while males had higher AL independent of age. Furthermore, LT and K decreased with AL, while ACD decreased with LT and increased with AL independent of age and gender. CONCLUSIONS: The estimates of the biometrics are obtained on a large sample of subjects and can serve as normative values for Lenstar LS900 in the Central European Caucasian population.

Vitamin D3 exerts immunomodulatory and memory improving properties in rats with lipopolysaccharide-induced inflammation.

INTRODUCTION: Vitamin D is a fat-soluble secosteroid, its primary function being regulation of calcium-phosphate homeostasis and maintenance of bone integrity and mineralization. Recently, pleotropic effects of this vitamin have been recognized, including an immunomodulatory role and involvement in normal brain development and functioning.

Pramipexole and tolcapone alleviate thermal and mechanical nociception in naive rats.

INTRODUCTION: Parkinson's disease (PD) is а neurodegenerative disorder characterized mainly by its motor symptoms. The non-motor symptoms including pain are increasingly recognized in the last few decades. Existing evidence suggests that the dopaminergic neurotransmission has an essential role in pain control. AIM: The aim of the present study was to investigate the antinociceptive effect of dopaminergic drugs pramipexole and tolcapone against chemical and thermal stimuli in naive rats. MATERIALS AND METHODS: Male Wistar rats divided into 8 groups (n=8): saline; diclofenac 25 mg/kg body weight (bw) (positive control); pramipexole 0.5; 1 and 3 mg/kg bw; tolacapone 5; 15 and 30 mg/kg bw. Paw pressure and plantar tests were performed. Paw withdrawal pressure and latent time were measured. Statistical analysis was done by SPSS 19. RESULTS: In the paw pressure test, pramipexole, in a dose of 1 and 3 mg/kg bw and tolcapone in a dose of 30 mg/kg bw, increased significantly the latency at 1, 2, and 3 hours compared to saline (p<0.05). In the plantar test, only the highest dose of pramipexole reached significance at 3 hours compared to the control rats (p<0.05). In contrast to pramipexole the three experimental groups with tolcapone markedly increased the latent time at 1 and 3 hours compared to saline (p<0.05). CONCLUSIONS: Pramipexole and tolcapone reduce mechanical and thermal nociception in naïve rats by enhancing dopaminergic neurotransmission at both spinal and supraspinal levels. In addition, tolcapone stimulates noradrenergic mediation which may contribute to its antinociceptive effect.

Dopaminergic agonist pramipexole improves memory and increases IL-10 production in LPS-challenged rats.

OBJECTIVES: A variety of cytokines are involved in cognitive functioning. Balance restoration between protective and degenerative neuro-inflammation is of great interest in newer therapeutic approaches. In the current study, we investigated the effect of pramipexole (PMX) on memory functions, hippocampal amyloid deposition, serum cytokines, and brain-derived neurotrophic factor (BDNF) levels in lipopolysaccharide (LPS) challenged-rats. MATERIALS AND METHODS: Male Wistar rats were divided into 5 groups (n=8): control (saline), lipoppolysacharide (LPS 250 mcg/kg bw), and experimental groups (LPS and PMX 0.5, 1, and 3 mg/kg bw). Learning and memory were assessed by the novel object recognition test (NORT), Y-maze, and step-through test. Immunological and histological assays were performed. RESULTS: In memory tasks, LPS-challenged rats showed reduction in the observed parameters. In NORT, PMX 1 mg/kg increased recognition index compared with controls, whereas the other two doses increased this index only against the LPS-control. In Y-maze, all doses of PMX significantly had increased alternation when compared with LPS. In the step-through test, only the lowest dose of PMX extended the latency compared with LPS. Histological examination revealed that PMX at doses of 0.5 and 1 mg/kg reduced amyloid deposition in the hippocampus. Interleukin (IL)-10 serum levels were elevated by 1 mg/kg PMX. Tumor necrosis factor (TNF)-α and transforming growth factor (TGF)-ß1 serum levels remained under the detectable minimum in all experimental groups. PMX at all doses significantly decreased BDNF serum concentration. CONCLUSION: In rats with LPS-induced neuro-inflammation PMX improved hippocampal-dependent memory and exerted immuno-modulatory effects by increasing IL-10.

Effects of Pramipexole on Learning and Memory Processes in Naïve and Haloperidol-challenged Rats in Active Avoidance Test.

BACKGROUND: Parkinson's disease (PD) is the second most common neurode-generative disease, usually detected by its motor symptoms. The non-motor symptoms, including cognitive deficits, have been of great interest to researchers in the last few decades. AIM: To assess the effect of pramipexole on learning and memory in naïve and haloperidol-challenged rats. MATERIALS AND METHODS: Male Wistar rats divided into 9 groups (n=8): naïve - saline, pramipexole 0.5; 1 and 3 mg/kg bw; Haloperidol groups - saline, haloperidol, haloperidol + pramipexole 0.5; 1 and 3 mg/kg bw. Two-way active avoidance test (TWAA) and activity cage were performed. The studied parameters were: number of conditioned and unconditioned responses, vertical and horizontal movements. Statistical analysis was done using SPSS 19. RESULTS: The naïve experimental groups significantly increased the number of conditioned responses during the tests for short- and long-term memory, compared with the saline groups (p<0.05). During the short-memory test only the animals with the lowest dose of PMX significantly increased the number of unconditioned responses whereas during the long-term memory test all experimental groups increased the number of escapes in comparison with the saline groups (p<0.05). Challenge dose of haloperidol attenuates learning and memory in pramipexol treated rats. Only the highest dose of pramipexol showed significant increase in conditioned and unconditioned responses compared with the haloperidol group (p<0.05). CONCLUSION: Pramipexole improves learning and memory in naïve rats by enhancing dopaminergic neurotransmission. This is probably not the only mechanism involved. This is confirmed by the decrease in learning and memory ability in rats with haloperidol-challenge.

Catechol-o-methyltransferase inhibitor tolcapone improves learning and memory in naïve but not in haloperidol challenged rats.

OBJECTIVES: Dopamine plays an important role in cognitive functions. Inhibition of the dopamine-degrading enzyme catechol-O-methyltransferase (COMT) may have beneficial effects. Our aim was to assess the effect of COMT inhibitor tolcapone (TCP) on learning and memory in naïve and haloperidol-challenged rats. MATERIALS AND METHODS: Male Wistar rats were divided into 9 groups (n=8): naïve-saline, tolcapone 5; 15 and 30 mg/kg BW; haloperidol (HP) challenged-saline, haloperidol, haloperidol+tolcapone 5; 15 and 30 mg/kg BW. Two-way active avoidance test (TWAA), elevated T-maze, and activity cage were performed. Observed parameters were: number of conditioned responses (CR) and unconditioned responses (UCR), working memory index, and vertical and horizontal movements. RESULTS: Naïve rats with 30 mg/kg BW TCP had a significantly increased number of CR and UCR during the long-term memory test. The animals with 5 mg/kg BW TCP significantly increased the number of UCR during the two retention tests. In haloperidol-challenged rats, the three experimental groups decreased the number of CR and UCR during the learning session and the two memory tests, compared to the saline group. There was no significant difference between the HP-challenged rats treated with TCP and the haloperidol control group. All experimental naïve groups had significantly increased working memory index whereas none of the HP-challenged groups showed significant increase in this parameter. CONCLUSION: Our results demonstrate that in naïve rats tolcapone improves memory in the hippocampal-dependent TWAA task and spatial working memory in T-maze.

Biological Screening of Novel Structural Analog of Celecoxib as Potential Anti-Inflammatory and Analgesic Agent.

Background and objectives: The clinical use of non-steroidal anti-inflammatory drugs is limited due to high incidence of adverse drug reactions. The pyrrole heterocycle is included in the chemical structure of a number of drugs with various activities and shows relatively good tolerability and safety. The objectives of our study were to evaluate the analgesic and anti-inflammatory activity, as well as possible organ toxicity, of 2-[3-acetyl-5-(4-chloro-phenyl)-2-methyl-pyrrol-1-yl]-3-(1H-indol-3-yl)-propionic acid (compound 3g), a novel N-pyrrolylcarboxylic acid structurally similar to celecoxib. Materials and methods: All experiments were performed on 6-week-old male Wistar rats divided into parallel groups (n = 8). Antinociception was assessed using animal pain models with thermal and chemical stimuli (paw withdrawal, tail-flick, and formalin tests). Criteria for the analgesic effect were increased latency in the paw withdrawal and tail-flick tests and decreased paw licking time in the formalin test compared to animals treated with saline (control). Anti-inflammatory activity was measured using a carrageenan-induced paw edema model; the criterion for anti-inflammatory effect was decreased edema compared to control. Blood samples were obtained after animals were sacrificed to assess possible organ toxicity. Statistical analysis was performed with IBM SPSS 20.0. Results: 2-[3-Acetyl-5-(4-chloro-phenyl)-2-methyl-pyrrol-1-yl]-3-(1H-indol-3-yl)-propionic acid had analgesic action against chemical stimulus after single and multiple administration and against thermal stimulus after single administration. Compound 3g significantly suppressed carrageenan-induced paw edema after both single and continuous administration. After continuous administration, hematological tests showed that compound 3g decreased leukocyte and platelet levels and elevated serum creatinine levels. Conclusions: Antinociception with the tested compound is most likely mediated by spinal, peripheral, and anti-inflammatory mechanisms. Possible tolerance of the analgesic action at the spinal level develops after continuous administration. Anti-inflammatory activity is significant and probably the leading cause of antinociception. After multiple administration, compound 3g showed signs of potential nephrotoxicity and antiplatelet activity, as well as suppression of leukocyte levels.

Experimental Study of the Analgesic Effect of the Antidepressant Escitalopram.

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.

Antioxidant Activity of Dry Birch (Betula Pendula) Leaves Extract.

BACKGROUND: Betula pendula is widespread in Europe and Asia. It has been used in traditional medicine since ancient times. Birch leaf extracts are known to exhibit a number of pharmacological activities. Antioxidant activity has also been reported. AIM: The aim of this work was to investigate the antioxidant activity of a dry leaf extract from Betula pendula Roth. MATERIALS AND METHODS: The total flavonoid content was determined. Some of the most commonly used methods were applied to evaluate the antioxidant capacity of the extract in vitro and in vivo. The ability of the extract to scavenge DPPH free radicals was evaluated by the method described by Brand-Williams with suitable modifications. ABTS decolorization assay was also applied. The in vivo assay was performed after acute and chronic administration of the extract into white albino rats, in a dose of 100 and 500 mg/kg bw. The antioxidant potential of the plasma was determined using FRAP reagent. RESULTS: A total flavonoid content of 42.5 mg/g was found, expressed as quercetin. The antioxidant activity against ABTS was concentration and time dependent. For example the concentration of 200 µg/ml led to 70.95% - 99.46% scavenging activity. DPPH scavenging activity was found to be about 98% at a concentration of 80 µg/ml. The extract possesses antioxidant potential, comparable with that of Trolox, in acute application. In chronic application, poorer results are observed, probably due to biotransformation and elimination processes. CONCLUSION: Dried birch leaf extract has a relatively high antioxidant potential and could be used as a natural source of antioxidants.

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.

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)-1ß, IL-12Bp40, interferon-γ (INF-γ)) and anti-inflammatory cytokines (IL-4, IL-10, tumor growth factor-ß (TGF-ß)) 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-1ß, IL-12Bp40) in rat serum and restored the level of anti-inflammatory cytokines (IL-4, IL-10, TGF-ß) 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.

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)-1ß, IL-12Bp40, interferon (INF)-γ) and anti-inflammatory cytokines (IL-4, IL-10, tumor growth factor (TGF)-ß) 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-1ß in rat serum and restored the level of anti-inflammatory cytokines (IL-10, TGF-ß) 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.

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

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.

Effect of Low Dose Atorvastatin Therapy on Baroreflex Sensitivity in Hypertensives.

INTRODUCTION: Impaired baroreflex function is associated with a shift in autonomic balance towards sympathetic dominance, which may play important role in the development of arterial hypertension and consequent target organ damage. AIM: To determine the effect of treatment on the cardiovascular autonomic modulation expressed by baroreflex sensitivity (BRS) in hypertensives. METHODS: A total of one hundred fourteen hypertensive patients (58 male/56 female, 65 ± 13 years of age, BMI 30 ± 3.4 kg/m(2)) were enrolled. Control group of 20 subjects with normal blood pressure (BP) (ten male/ten female, 59 ± 8 years of age, body mass index 28.3 ± 2.5 kg/m(2)) without any treatment was also studied. BRS and BRSf were determined by the sequence and spectral method: a 5-min on-invasive beat-to-beat recording of blood pressure and R-R interval with use of Collin CBM-7000 monitor, controlled breathing at a frequency of 0.1 Hz. RESULTS: Significant negative correlation between spontaneous BRS and BP was present in hypertensives (r = -0.52, p < 0.001). All cohort of hypertensive patients had significantly lower BRS than subjects with normal blood pressure (p < 0.05). The greatest decline in BRS values was in hypertensive patients with metabolic syndrome, who had BRS values <5 ms/mmHg. Hypertensives with hypercholesterolaemia on low dose statin therapy (atrovastatin 20 mg) had higher BRS/BRSf values than statin free patients (p < 0.05). Only BRSf not BRS was significantly increased in hypertensives with beta-blockers. CONCLUSION: An inverse correlation between blood pressure and BRS is present in hypertensives. BRS and BRSf is higher in low dose statin-treated patients with essential hypertension.

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.

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.

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

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.