Reticuloendothelial function in acute noise stress.

Wistar strain albino rats of either sex were subjected to acute noise stress (3000 Hz at > 97 dB) for 30 minutes. Carbon clearance test was conducted in noise stressed animals immediately after the stress period. Significant (P < 0.001) increase of the clearance constant K was observed in stressed animals compared to the controls, indicating increased phagocytic activity of the reticuloendothelial system.     

Biochemical changes in acute noise stress in rats

The effects of acute auditory stress on certain biochemical parameters like blood corticosterone, total cholesterol, triglyceride, Serum glutamic pyruvic transaminase (SGPT) and Serum glutamic oxaloacetic transaminase (SGOT) were studied in albino rats. A significant increase was observed in the blood level of corticosterone, total cholesterol, SGOT and SGPT while a marked reduction was noticed in the Sr. triglyceride level. These data indicate that noise could be a potent stressor and cause disturbances in the biochemical parameters of the body. It is presumed that most of the effects are indirect, being manifested through the activation of autonomic nervous system which liberates catecholamines and hypothalamo pituitary adrenal axis responsible for the liberation of corticosteroids.     

The mechanism of the effect of acute stress on hexobarbital metabolism

The effect of acute stress (unilateral hind-leg ligation for 1 hr) on hepatic metabolism of hexobarbital (HB) was studied in the rat. A stress duration-response relationship was found for stress inhibition of HB metabolism. The hepatic microsomal protein content was not affected, but the hepatic microsomal cytochrome P-450 content was reduced approximately 45% by this stress treatment. Stress caused a twofold increase in plasma corticosterone level and had no effect on plasma corticosterone level of adrenalectomized rats. Hexobarbital metabolism was not affected by stress in adrenalectomized rats. Thus, the inhibition of hepatic HB metabolism by acute stress may be caused by the increased release of corticosterone induced by acute stress.     

Immunomodulatory activity of triphala on neutrophil functions

Immune activation is an effective as well as protective approach against emerging infectious diseases. The immunomodulatory activities of Triphala (Terminalia chebula, Terminalia belerica and Emblica officinalis) were assessed by testing the various neutrophil functions like adherence, phagocytosis (phagocytic index (P.I) and avidity index (A.I)) and nitro blue tetrazolium (NBT) reduction in albino rats. In recent years much attention is being focused on the immunological changes occur during stress. Noise (100 dB) stress for 4 h/d for 15 d, was employed to alter the neutrophil functions. The neutrophil function tests and corticosterone levels were carried out in eight different groups of animals, namely control, Triphala, noise-stress, Triphala noise-stress, and corresponding immunized groups were used. Sheep red blood cells (SRBC 5 x 10(9) cells per ml) were used for immunizing the animals that belongs to immunized groups. In Triphala administration (1 g/kg/d for 48 d), A.I was found to be significantly enhanced in the Triphala group, while the remaining neutrophil functions and steroid levels were not altered significantly. However the neutrophil functions were significantly enhanced in the Triphala immunized group with a significant decrease in corticosterone level was observed. Upon exposure to the noise-stress, the neutrophil functions were significantly suppressed and followed by a significant increase in the corticosterone levels were observed in both the noise-stress and the noise-stress immunized groups. These noise-stress-induced changes were significantly prevented by Triphala administration in both the Triphala noise-stress and the Triphala noise-stress immunized groups. Hence our study has divulged that oral administration of Triphala appears to stimulate the neutrophil functions in the immunized rats and stress induced suppression in the neutrophil functions were significantly prevented by Triphala.     

The effect of stress on the acute neurotoxicity of the organophosphate insecticide chlorpyrifos

A study was conducted to determine if multiple exposures to several stress paradigms might affect the anticholinesterase effect of subsequently administered organophosphate insecticide chlorpyrifos. Male Sprague-Dawley rats were subject to daily periods of restraint, swimming, a combination of the two, or neither of the two (controls) (n=8/group) for 5 days per week over a six-week period. The most profound stress, as measured by reduced body weight gain and elevated levels of plasma corticosterone, was swimming. On day 39 of the study, shortly after the daily stress episode, one half of the rats in each group was dosed with 60 mg/kg chlorpyrifos subcutaneously. This had no effect on subsequent levels of plasma corticosterone. There were no stress-related differences in the degree of chlorpyrifos-induced inhibition of brain acetylcholinesterase in animals sacrificed on day 43.     

The regulatory effect of mexidol on the hemoglobin level under acute stress conditions

Experiments on a group of 39 Wistar albino male rats showed that, 2 and 5 days after a model acute stress procedure, the total amount of erythrocytes is increased. This process is accompanied by a hypochromia of red cells and by a decrease in the concentration of serum iron. Single administration of mexidol (100 mg/kg) before stress induction prevents changes in the amount of blood erythrocytes, as well as in their saturation with hemoglobin. Mexidol also prevents a decrease in the level of serum iron. The drug does not influence the hematological parameters and iron concentration in blood serum of intact animals 2 and 5 days after injection.     

Mechanism of anti-inflammatory action of glycyrrhizin: effect on neutrophil functions including reactive oxygen species generation

The effect of glycyrrhizin on inflammatory mediators such as neutrophil functions including reactive oxygen species (ROS) generation was examined. Glycyrrhizin significantly decreased neutrophil-generated O2-, H2O2 and OH in a dose-dependent manner. However, the drug did not reduce any of the ROS generated in a cell-free, xanthine-xanthine oxidase system. The drug did not affect neutrophil chemotaxis or phagocytosis, either. The present study indicates that glycyrrhizin is not an ROS scavenger but exerts an anti-inflammatory action by inhibiting the generation of ROS by neutrophils, the most potent inflammatory mediator at the site of inflammation.     

Stimulatory effects of anti-rheumatic drugs on human neutrophil functions

Auranofin (AF), D-penicillamine (D-pen) and thiola are prescribed as disease-modifying drugs in the treatment of rheumatoid arthritis (RA). We have shown here that auranofin, 10(-8) to 10(-6) M, D-penicillamine, 10(-6) to 10(-3) M, thiola, 10(-7) to 10(-3) M, and the tripeptide thiol, glutathione, 10(-6) to 10(-3) M, enhanced f-met-leu-phe-induced lysosomal enzyme release and the phagocytic uptake of bacteria by up to 40%. The previously reported inhibitory effects of AF were only observed at concentrations in excess of those likely to be available to effector cells in vivo. The stimulatory effects of thiola and D-pen occurred at concentrations likely to be available to effector cells in vivo and, therefore, may be of greater clinical relevance. There is evidence that the drugs used in this study exert their effects via a thiol moiety and their therapeutic effect is preceded by an elevation of intracellular thiol levels.     

Sympathoadrenal-dependent sexually dimorphic effect of nonhabituating stress on in vivo neutrophil recruitment in the rat

Since stress both activates the sympathoadrenal axis and profoundly affects inflammation and inflammatory diseases, many of which are sexually dimorphic, we tested whether the effect of stress on neutrophil recruitment, a primary component of the acute inflammatory response, is sexually dimorphic. The effect of intermittent sound (over 4 days), a nonhabituating stress, on lipopolysaccharide (LPS)-induced recruitment of neutrophils was evaluated in vivo in the rat air pouch model. At 24 h following the last stress exposure, LPS-induced neutrophil recruitment was enhanced in male rats, but not in females. When gonadectomized prepubertally and tested as adults, stress significantly inhibited the magnitude of LPS-induced neutrophil recruitment in males, while it still had no effect in gonadectomized females. In males, following adrenal denervation, the increase in LPS-induced neutrophil recruitment produced by stress was prevented. Since these data suggest that the effect of stress is dependent on the sympathoadrenal axis, we tested the hypothesis that catecholamines mediate the stress effects.In male rats, the effect of stress on LPS-induced neutrophil recruitment was significantly attenuated by continuous administration of the beta-adrenergic receptor antagonist, propranolol (4 mg kg(-1) day(-1)), during sound stress exposure, and administration of isoproterenol (10 nmoles, i.v.) significantly increased neutrophil recruitment in males, an effect that was qualitatively and quantitatively similar to the effect of stress. Propranolol significantly increased neutrophil recruitment in nonstressed female rats, but did not significantly affect neutrophil recruitment in stressed females. These findings indicate a marked male sex hormone-dependent sexual dimorphism in the sympathoadrenal-dependent effect of stress on neutrophil migration, a primary component of the inflammatory response, and suggest that the sympathoadrenal axis contributes to this effect via release of epinephrine.     

The effect of acute oxidative stress on the ultrastructure of the perfused rat liver

Ageing and liver disease are associated with ultrastructural changes in the hepatic sinusoid. Because of the possibility that reactive oxygen species could mediate these processes, we examined the effect of acute oxidative stress on the ultrastructure of the intact liver. Rat livers were perfused ex vivo, in situ with hydrogen peroxide via the portal vein. The livers were then fixed and the ultrastructure of the liver tissue examined with transmission and scanning electron microscopy. The effects of hydrogen peroxide were largely confined to the perisinusoidal areas. The sinusoidal endothelial cells became swollen and more porous, with large gaps replacing sieve plates. The space of Disse showed an increase in volume and the density of hepatocyte projections decreased. Kupffer cell activation was noted. Little or no ultrastructural change was observed within the hepatocytes. Oxidative stress delivered via the portal vein dramatically alters the ultrastructure of the perisinusoidal regions of the liver. This process may contribute to the pathogenesis of disease and age-related changes in the liver.     

The effect of a selective CXCR2 antagonist (AZD5069) on human blood neutrophil count and innate immune functions

AimsThe aim of the present study was to investigate whether selective antagonism of the cysteine‐X‐cysteine chemokine receptor‐2 (CXCR2) receptor has any adverse effects on the key innate effector functions of human neutrophils for defence against microbial pathogens.MethodsIn a double‐blind, crossover study, 30 healthy volunteers were randomized to treatment with the CXCR2 antagonist AZD5069 (100 mg) or placebo, twice daily orally for 6 days. The peripheral blood neutrophil count was assessed at baseline, daily during treatment and in response to exercise challenge and subcutaneous injection of granulocyte‐colony stimulating factor (G‐CSF). Neutrophil function was evaluated by phagocytosis of Escherichia coli and by the oxidative burst response to E. coli.ResultsAZD5069 treatment reversibly reduced circulating neutrophil count from baseline by a mean [standard deviation (SD)] of −1.67 (0.67) ×10⁹ l^–1vs. 0.19 (0.78) ×10⁹ l^–1 for placebo on day 2, returning to baseline by day 7 after the last dose. Despite low counts on day 4, a 10‐min exercise challenge increased absolute blood neutrophil count, but the effect with AZD5069 was smaller and not sustained, compared with placebo treatment. Subcutaneous G‐CSF on day 5 caused a substantial increase in blood neutrophil count in both placebo‐ and AZD5069‐treated subjects. Superoxide anion production in E. coli‐stimulated neutrophils and phagocytosis of E. coli were unaffected by AZD5069 (P = 0.375, P = 0.721, respectively vs. baseline, Day 4). AZD5069 was well tolerated.ConclusionsCXCR2 antagonism did not appear adversely to affect the mobilization of neutrophils from bone marrow into the peripheral circulation, phagocytosis or the oxidative burst response to bacterial pathogens. This supports the potential of CXCR2 antagonists as a treatment option for diseases in which neutrophils play a pathological role.     

Aberrant neutrophil functions in stable chronic obstructive pulmonary disease: The neutrophil as an immunotherapeutic target

Chronic obstructive pulmonary disease (COPD) is a common, progressive and debilitating chronic inflammatory condition affecting the lungs, with significant systemic manifestations and co-morbidities. Smoking cigarettes is the main risk factor, but only a fifth of smokers have clinically significant airflow obstruction and the inflammation persists after smoking cessation. This suggests that smoking (and exposure to other inhaled toxins) may be necessary but not sufficient to cause COPD. Neutrophils are believed central to COPD and their accumulation and degranulation are associated with tissue damage, increased inflammation and disordered tissue repair. It was assumed that neutrophil activity and function were appropriate in COPD, responding to the presence of high levels of inflammation in the lung. However more recent studies of neutrophil function (including migration, reactive oxygen species generation, degranulation, phagocytosis and extracellular trap (NET) production) suggest that there is a general impairment in COPD neutrophil responses that predispose towards increased inflammation and reduced bacterial clearance. This may be amenable to correction and manipulating neutrophil intracellular pathways (such as phosphoinositide-3-kinase signalling) appears to restore some key COPD neutrophil responses. Targeting neutrophil intra-cellular signalling may provide a means to normalise neutrophil behaviour in COPD. This could lead to improvements in disease outcomes by reducing extraneous inflammatory burden. However further studies are needed to determine if these findings are relevant in vivo and whether this would impact positively upon health and disease.     

The effect of mexidol on the process of glycolysis in rats under acute stress conditions

Pretreatment with mexidol (100 mg/kg) protected white male rats (n = 29) under the conditions of acute (3 h) immobilization stress. This was evidenced by monitoring of the levels of glucose, pyruvic, and lactic acid in the rat brain, liver, spleen, thymus, and blood serum. In both brain and peripheral organs, mexidol the shifted the equilibrium toward pyruvate--an energetically more favorable substrate of enzymatic oxidation.     

Effects of lead on neutrophil functions in occupationally exposed workers

Chemotactic and intracellular killing activity of neutrophils were examined in 25 male lead-exposed workers from storage-battery plants and compared to 25 healthy males with no history of lead exposure. Lead exposure was assessed using blood lead levels measured by atomic absorption spectrophotometry and zinc protoporphyrin levels assayed by hematofluorometry. Chemotaxis was carried out in Boyden chambers using zymosan activated serum as chemotactic stimulus. Intracellular killing activity of neutrophils was measured using nitroblue tetrazolium reduction test, measured of 515 nm in spectrophotometry. In lead-exposed workers a significant decrease in chemotaxis and random migration of neutrophils (p<0.001) was observed compared to controls. Intracellular killing activity of polymorphonuclear leukocytes have also seemed to be slightly but not significantly reduced. These results suggest that human chronic exposure to lead may diminish neutrophil function in man.     

Analgesic effect of environmental noise: a possible stress response in rats

Environmental noise is a known stress, which induces alterations of various physiological responses in individuals exposed to it. Stress has been shown to cause changes in the perception of various sensations including pain and stress-induced analgesia has been observed following exposure to a diverse set of stimuli. To examine the algesic behavior of rats exposed to loud environmental noise, for long duration, we used an environment simulating chamber and conducted the tail flick test for the assessment of pain. The rats were divided into groups and subjected to loud noise for test sessions lasting 1 h, 2 h or 3 h in trials of 5 consecutive days. The noise was of two kinds--a continuous shrill noise (pure tone 92 dB & 98 dB) and an intermittent heavy artillery noise (white noise 102 dB). 15 min before and after each test session, tail flick latencies (TFL) were recorded at 5 min interval. The TFL recorded were normalised to an Index of Analgesia (IA) and the readings statistically analyzed using the F test (ANOVA), the significance being obtained by Tukey's test (at 5% level). The results revealed a significant increase in the TFL and the IA (P < 0.0001) in all the test groups demonstrating a significant analgesic response in rats subjected to noise stress. The analgesia was maximum immediately after noise exposure and declined with time. It was found to be directly related to the duration of exposure, the intensity and the characteristics of the noise with loud intermittent (white) noise and longer duration of exposure producing more analgesia.     

Hawthorn extract inhibits human isolated neutrophil functions

Hawthorn extract is a popular herbal medicine given as adjunctive treatment for chronic heart failure. In contrast to the cardiac properties of hawthorn extract, its anti-inflammatory effect has been scarcely investigated. This study examines the effects of a dry extract of leaves and flowers of Crataegus laevigata on various functional outputs of human neutrophils in vitro. Incubation of human neutrophils obtained from peripheral blood of healthy donors with C. laevigata extract (0.75-250 microg/ml) inhibited N-formyl-Met-Leu-Phe (FMLP)-induced superoxide anion generation, elastase release and chemotactic migration with potency values of 43.6, 21.9, and 31.6 microg/ml, respectively. By contrast, serum-opsonized zymosan-induced phagocytosis was unaltered by plant extract. C. laevigata extract (125 microg/ml) reduced FMLP-induced leukotriene B(4) production and lipopolysaccharide-induced generation of tumour necrosis factor-alpha and interleukin-8. Extract inhibited FMLP-induced intracellular calcium signal with potency of 17.4 microg/ml. Extract also markedly inhibited the extracellular calcium entry into calcium-depleted neutrophils, and the thapsigargin-induced intracellular calcium response. In conclusion, C. laevigata extract inhibited various functional outputs of activated human neutrophils which may be relevant to the pathophysiology of cardiac failure.     

Hypochlorous acid inhibition by acetoacetate: implications on neutrophil functions

Type-1 diabetic patients experience hyperketonemia caused by an increase in fatty acid metabolism. Thus, the aim of this study was to measure the effect of ketone bodies as suppressors of oxidizing species produced by stimulated neutrophils. Both acetoacetate and 3-hydroxybutyrate have suppressive effect on the respiratory burst measured by luminol-enhanced chemiluminescence. Through measurements of hypochlorous acid production, using neutrophils or the myeloperoxidase/H2O2/Cl- system, it was found that acetoacetate but not 3-hydroxybutyrate is able to inhibit the generation of this antimicrobial oxidant. The superoxide anion scavenging properties were confirmed by ferricytochrome C reduction and lucigenin-enhanced chemiluminescence assays. However, ketone bodies did not alter the rate of oxygen uptake by stimulated neutrophils, measured with an oxygen electrode. A strong inhibition of the expression of the cytokine IL-8 by cultured neutrophils was also observed; this is discussed with reference to the antioxidant-like property of acetoacetate.     

中性粒细胞参与的ADCC对猪带绦虫六钩蚴的杀伤作用

本文用体外培养方法,观察了人体中性粒细胞、特异性抗体、补体等因子对猪带绦虫六钩蚴的杀伤作用。实验结果表明:单纯中性粒细胞对六钩蚴无明显的影响,但在抗体参与下,对虫体有明显的杀伤作用。再加入补体,杀伤作用显著增强。用羊抗人IgG血清吸附抗体,可使虫体的死亡率明显降低。提示:IgG依赖、中性粒细胞介导的细胞毒作用(ADCC)参与人体抗囊虫感染的免疫机理。     

The effect of sesquiterpene lactones on the release of human neutrophil elastase

Sesquiterpene lactones (SLs) are natural products responsible for the anti-inflammatory activity of a variety of medicinal plants, mainly from the Asteraceae family. Here, we investigated whether they also influence the process of exocytosis of pro-inflammatory enzymes, such as the human neutrophil elastase (HNE). Altogether, eight structurally different SLs from the eudesmanolide, guaianolide, pseudoguaianolide, and germacranolide type were studied. Neutrophils were isolated from fresh human blood. After pre-incubation with different concentrations of the respective SL and cytochalasin B, the exocytosis of elastase was initiated either by platelet activating factor or N-formyl-methionyl-leucyl-phenylalanine. Inhibition of HNE release was measured by p-nitroaniline formation. The SLs exhibited an inhibitory effect on elastase release from neutrophils challenged either by platelet activating factor or N-formyl-methionyl-leucyl-phenylalanine. Concentration-response curves were recorded and the IC(50) values ranged from 2 to 30 microM. Studies on isolated HNE showed that a selective direct inhibition on HNE can be excluded. Interestingly, the inhibitory activity did not correlate with the number of alpha,beta-unsaturated carbonyl functions. The structure-activity relationship and the molecular mechanism are discussed.     

Immunomodulatory effects of Santolina chamaecyparissus leaf extracts on human neutrophil functions

Context: Santolina chamaecyparissus L. (Asteraceae) is an aromatic plant wide spread in the Mediterranean region. It is used in folk medicine for its anti-inflammatory properties.

Objective: The effects of S. chamaecyparissus aqueous extract (SCAE) and polyphenolic extract (SCPE) on human polymorphonuclear neutrophil (PMN) degranulation, chemotaxis, phagocytosis, and microbicidal capacity were examined in vitro.

Materials and methods: Aqueous and polyphenolic extracts were prepared from S. chamaecyparissus leaves. The elastase release was used as a marker for measuring PMN degranulation, while chemotaxis was performed using a 48-microwell chemotaxis chamber. The phagocytosis and the microbicidal capacity were evaluated using fresh cultures of Candida albicans.

Results: The treatment of neutrophils with different concentrations (10–200?µg/ml) of SCAE and SCPE caused a significant (p?<?0.001) and dose-dependent inhibitory effect on elastase release in fMLP/Cytochalasin B (CB)-stimulated neutrophils. Indeed, 100?µg/ml of SCAE exerted an inhibitory effect of 51.97?±?6.2%, whereas SCPE at the same concentration abolished completely PMN degranulation. Moreover, both extracts inhibited markedly (p?<?0.01) fMLP-induced chemotactic migration. At 200?µg/ml, SCAE and SCPE exerted an inhibitory effect of 54.61?±?7.3% and 57.71?±?7.44%, respectively. In addition, a decline in both phagocytosis and microbicidal capacity against Candida albicans was observed when PMNs were exposed to 100 and 200?µg/ml of SCAE or SCPE.

Conclusion: The exerted effects on neutrophil functions support the anti-inflammatory activity and show new mechanisms of action and effectiveness of S. chamaecyparissus leaf extracts. This plant may be considered as an interesting source of anti-inflammatory and immunomodulatory agents.