Antiinflammatory effects of natural tetranortriterpenoids isolated from Carapa guianensis Aublet on zymosan-induced arthritis in mice

Objective We investigated the antiinflammatory properties of a derived fraction of tetranortriterpenoids (TNTP) obtained from the seeds of Carapa guianensis Aublet. Material and methods Zymosan-induced arthritis and pleurisy in Swiss and C57/Bl6 mice (n = 10 per group). Western blot analysis was performed to analyze nuclear factor-κB (NFκB) translocation in mice peritoneal macrophages stimulated in vitro with zymosan (500 μg/ml). ELISA was performed to evaluate cytokine levels in knee joints. Values of p ≤ 0.05 were regarded as significant. Results Zymosan intra-articular (i. a.) injection (500μg/ cavity) induced a significant increase in knee joint diameter within 6 h, peaked within 24 h and remained above control values for 20 days. Orally-given (p. o.) TNTP (100–200 mg/ kg) inhibited zymosan-induced increase in knee joint diameter and protein extravazation into synovial cavity within 6 h. TNTP (100–200 mg/kg, p. o.) also inhibited total leukocyte influx into the synovial space and tissue, as well as into the mice pleural cavity, due to neutrophil impairment 6 h after zymosan stimulation. The increase in TNF-α, IL-1β and CXCL8/IL-8 levels that were detected in knee synovial extracts obtained from zymosan-stimulated mice was also inhibited by TNTP (100 mg/kg, p. o.). Moreover, the incubation of mice peritoneal macrophages with TNTP (100 μg/ml) inhibited zymosan (500 μg/ml)-induced NFκB translocation into the nucleus 6 h after stimulation. Conclusion Taken together, these results indicate that TNTP present an important antiinflammatory effect, inhibiting zymosan-induced arthritis in mice via the impairment of TNF-α, IL-1β and CXCL8/IL-8 generation, as well as NFκB signaling pathway. Received 7 October 2005; returned for revision 16 January 2006; accepted by M. Parnham 22 May 2006     

Effect of Intranasal Administration of Anti-Glutamate Antibodies after Stress Exposure on the Stress Response

We studied the dose-dependent effect of antibodies to glutamate on the stress response in C57Bl/6 mice. The antibodies were administered immediately after stress exposure. Intranasal administration of antibodies to glutamate in doses of 150 and 250 μg/kg immediately after stress exposure was shown to reduce the stress response under conditions of combined restraint stress. This effect was most pronounced after treatment with antibodies in a dose of 250 μg/kg: we revealed a decrease in the number and severity of erosive and ulcerative lesions in the gastric mucosa, i.e. anti-glutamate antibodies have a protective effect.     

Chronic Cocaine Injections Attenuate Behavioral Response of κ-Opioid Receptors to U-50,488H Agonist

Chronic injections of cocaine (20 mg/kg daily for 10 days) increase activity and decrease anxiety in male C57Bl/6j mice in comparison with animals chronically injected with normal saline. U-50,488H (κ-opioid receptor agonist; 2.5 mg/kg) produced an anxiolytic effect in animals preinjected with normal saline and had no effect in animals chronically injected with cocaine. Presumably, chronic activation of dopaminergic systems caused by cocaine injections is paralleled by desensitization of k-opioid receptor system. __________ Translated from Byulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 140, No. 9, pp. 305–307, September, 2005     

Effects of zoosocial conflict on immunological reactivity of C57Bl/6 mice

In aggressive C57Bl/6 mice, the immune response is shown to be enhanced after 20 confrontations with submissive mice. In submissive mice, the response is inhibited after 10–20 confrontations with aggressive partners. It is concluded that stimulation and inhibition of the immune response are associated with the formation of a neurochemical set which is dopaminergic in aggressive mice and serotoninergic in submissive ones. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, No. 11, pp. 541–543, November, 1996     

Naloxone Effects on Behavior of Inbred Mice with Different Response to Emotional Stress in Open Field Test

Effects of nonspecific opiate receptor antagonist naloxone in doses of 0.1, 0.5, 1.0, 5.0, 10.0 mg/kg on open field behavior and spontaneous motor activity were studied in male BALB/c and С57Bl/6 mice. Differently directed effects of naloxone on behavioral parameters of emotional-stress reaction in BALB/c and С57Bl/6 mice were observed. Naloxone increased motor activity in the open field test in BALB/c mice, but decreased it in С57Bl/6 mice. In the absence of stress, naloxone in the studied dose range did not affect spontaneous motor activity in С57Bl/6 mice, and significantly reduced activity in BALB/c mice in doses 0.5 and 1.0 mg/kg.     

Immune Responses on Activation of Pre- and Postsynaptic Serotonin 5-HT1A Receptors in Mice with Depression-Like States

The development of a depression-like state in C57BL/6 J mice is accompanied by significant reductions in immune responses. Administration of the selective agonist of 5-HT_1A receptors 8-OH-DPAT to these animals at doses affecting both presynaptic receptors (0.1 mg/kg) and postsynaptic receptors (1.0 mg/kg) did not alter the number of IgM antibody-forming cells (AFC) in the spleen at the peak of the immune response, i.e., day 4 after administration of sheep erythrocytes, in mice with depression-like behavior. At the same time, activation of presynaptic 5-HT_1A receptors in control mice (without experience of victory or defeat) induced increases in the immune response, while stimulation of postsynaptic receptors led to immunosuppression. The question of decreases in the sensitivity of pre- and postsynaptic 5-HT_1A receptors during formation of depression-like behavior and the role of the functional activity of this type of receptor in the development of the immune responses in these conditions is discussed.     

A neurotoxic regimen of methamphetamine exacerbates the febrile and neuroinflammatory response to a subsequent peripheral immune stimulus

Methamphetamine (MA) use is associated with activation of microglia and, at high doses, can induce neurotoxicity. Given the changes in the neuroinflammatory environment associated with MA, we investigated whether MA administration would interfere with the thermoregulatory and neuroinflammatory response to a subsequent peripheral immune stimulus. C57BL6/J mice were given four i.p. injections of either 5 mg/kg MA or saline at two hour intervals. Twenty-four hours following the first MA injection, mice were given 100 μg/kg LPS or saline i.p. and blood and brains were collected. Here we report that mice exposed to MA developed higher fevers in response to LPS than did those given LPS alone. MA also exacerbated the LPS-induced increase in central cytokine mRNA. MA alone increased microglial Iba1 expression and expression was further increased when mice were exposed to both MA and LPS, suggesting that MA not only activated microglia but also influenced their response to a peripheral immune stimulus. Taken together, these data show that MA administration exacerbates the normal central immune response, most likely by altering microglia.     

The Role of Serotonin Receptors in Delta-Opioid Immunosuppression

Studies in CBA mice and Wistar rats demonstrated the involvement of serotonin (5-HT) receptors in immunosuppression evoked using the selective δ2 opioid receptor (δ2-OR) agonist DSLET (100 μg/kg). This opioid effect was seen in conditions of selective activation of 5-HT_1A autoreceptors with 8-OH-DPAT (0.1 mg/kg) and in conditions of prior blockade of postsynaptic 5-HT_1A and 5-HT_2A receptors with WAY-100635 and ketanserin (1 and 3 mg/kg). The question of the different contributions of these types of 5-HT receptor to δ-induced suppression of the immune response is discussed.     

Morphofunctional characteristic of the immune system in BALB/c and C57BL/6 mice

Inbred animals serve as an adequate model to study the role of genetic factors in adaptive, disadaptive, and pathological processes. Morphofunctional study of the immune system was performed on intact BALB/c and C57Bl/6 mice. The structural and functional parameters of the immune system in BALB/c and C57Bl/6 mice differ under physiological conditions. In BALB/c mice, volume density of T zone in the spleen and production of IL-2, IL-3, IL-4, IL-10, and TNF-α were much higher than in C57Bl/6 mice. However, IL-12 production in BALB/c mice was lower than in C57Bl/6 mice. C57Bl/6 mice were characterized by higher cytostatic activity of splenic NK cells. The observed interstrain differences are genetically determined and contribute to the type of adaptive processes and different sensitivity of these mice to pathogenic agents.     

Differential effect of hyperglycaemia on the immune response in an experimental model of diabetes in BALB/cByJ and C57Bl/6J mice: participation of oxidative stress

Diabetes is associated with an increased risk of death from infectious disease. Hyperglycaemia has been identified as the main factor contributing to the development of diseases associated with diabetes mellitus. However, experimental evidence indicates individual susceptibility to develop complications of diabetes. In this context, the aim of this work was to study the immune response in a streptozotocin‐induced type 1 diabetes in two mouse strains: BALB/cByJ and C57Bl/6J. The participation of hyperglycaemia and oxidative stress was also analysed. Diabetic BALB/cByJ mice showed a decrease in both the in‐vivo and in‐vitro immune responses, whereas diabetic C57Bl/6J mice had higher blood glucose but exhibited no impairment of the immune response. The influence of hyperglycaemia over the immune response was evaluated by preincubation of lymphocytes from normal mice in a high glucose‐containing medium. T and B cells from BALB/cByJ mice showed a decrease in cell viability and mitogen‐stimulated proliferation and an increase in apoptosis induction. An increase in oxidative stress was implicated in this deleterious effect. These parameters were not affected in the T and B lymphocytes from C57Bl/6J mice. In conclusion, BALB/cByJ mice were sensitive to the deleterious effect of hyperglycaemia, while C57BL/6J were resistant. Although an extrapolation of these results to clinical conditions must be handled with caution, these results highlight the need to contemplate the genetic background to establish models to study the deleterious effect of diabetes in order to understand phenotypical variations that are of clinical importance in the treatment of patients.     

Genetic analysis of anxiety-related behaviors and responses to benzodiazepine-related drugs in AXB and BXA recombinant inbred mouse strains

Recombinant inbred (RI) strains derived from the C57BL/6J and A/J mouse strains were used for behavioral studies designed to estimate the number and location of chromosomal loci responsible for anxiety-related behaviors and differential sensitivity to agonists and inverse agonists of the γ-aminobutyric acid_A (GABA_A)/benzodiazepine receptor complex. The phenotypes of the parental inbred strains and of 28 RI strains were characterized for the number of transitions in the light ⇆ dark exploratory model, anxiolytic response to diazepam, vertical and ambulatory activities in an open field, and sensitivity to the convulsant properties of methyl-β-carboline-3-carboxylate (β-CCM). The strain distribution patterns and estimates of the minimal number of loci obtained for each trait suggest that multiple chromosomal loci contribute to differences in anxiety-related behavioral phenotypes and the behavioral responses to diazepam and β-CCM between C57BL/6J and A/J mice. The best probabilities of linkage were found between the variables characterizing response to diazepam and loci on chromosomes 1 (Xmv-41) and 10 (D10Mit2) and between the sensitivity to the convulsant actions of β-CCM and locusD15Mit5 on chromosome 15.     

Effect of Ladasten on the Content of Cytokine Markers of Inflammation and Behavior of Mice with Experimental Depression-Like Syndrome

The effects of ladasten and reference product imipramine (10 mg/kg) on the content of cytokines TNF-α, IL-6, IL-10, IL-1α, IL-2, IL-4, IL-5, IL-17, IFN-γ, and GM-CSF and behavior of male C57Bl/6 mice were studied on the model of a depression-like state induced by a single intraperitoneal injection of bacterial LPS in a dose of 100 μg/kg. Ladasten was injected 5 times in doses of 30 and 50 mg/kg. LPS was administered 1 h after the last injection of the test agents. Behavioral disturbances and significant increase in the concentration of TNF-α and IL-6 in blood plasma were observed 2 h after LPS treatment. Ladasten was more potent than imipramine in decreasing the content of proinflammatory cytokines TNF-α and IL-6 and preventing the development of behavioral disturbances in mice. Antiasthenic drug ladasten was shown to decrease the elevated level of proinflammatory cytokines TNF-α and IL-6 after LPS treatment. Further studies should be performed to develop new indications for the use of ladasten in adjuvant therapy of depression.     

Immune response during activation of pre- and postsynaptic serotonin 5-HT(1A) receptors in C57Bl/6J mice at various stages of a depression-like state

The development of a depression-like state in C57Bl/6J mice with repeated defeat experience (10 and 20 days) was accompanied by inhibition of the immune response (evaluated from the number of IgM antibody-producing cells). Activation of postsynaptic 5-HT(1A) receptors with a selective agonist 8-OH-DPAT (1.0 mg/kg) in these animals had no effect on the immune reaction. In mice without the experience of confrontations, stimulation of postsynaptic receptors caused a decrease in the number of IgM antibody-producing cells at the peak of the immune response induced by sheep erythrocytes (5×10(8) cells). However, the count of these cells remained unchanged in mice with a depression-like state (irrespective of the stage of disorder). Activation of presynaptic 5-HT(1A) receptors with 8-OH-DPAT (0.1 mg/kg) in control animals and mice with 10-day defeat experience was followed by immune stimulation. These changes were not observed in mice with a depression-like state caused by 20-day social stress.     

Effect of Acute and Chronic Buspirone Administration on Communicativeness of Mice with Experience of Defeats in Social Conflicts

We studied the effect of 5-HT1A receptor agonist buspirone on behavior of male C57Bl/6J mice in the “partition” test, which reflects communicativeness of animals. Single administration of buspirone (1 mg/kg) to intact mice and animals experienced defeats in 20 intermale confrontations impaired their communicativeness, especially in intact animals. On the contrary, administration of buspirone (1 mg/kg) to losers starting from day 5 of intermale confrontations for 2 weeks produced a positive effect and prevented impairment of communicativeness by day 20 of confrontations. The role of brain 5-HT1A receptors in these processes is discussed.     

Effect of Radioprotector Indralin on the Course of Acute GVH Disease

The effect of radioprotector indralin on the graft-versus-host reaction was studied on the model of acute GVH disease induced in mice by intraperitoneal transplantation of 40×10⁶ semiallogenic splenocytes. The effect was evaluated by animal mortality from GVH disease. Recipients were male F₁(CBA × C57Bl/6) mice exposed to 7 Gy 24 h before transplantation. Donors were male C57Bl/6 mice. Indralin, intraperitoneally injected in a dose of 100 mg/kg 5 min after irradiation attenuated the severity of GVH disease. It eliminated phase I of acute GVH reaction and shifted to the right the dynamics of mortality. Estimated time of 50% mortality (LT₅₀) was prolonged by more than 4 days (the parameter increased by 31.1%). Two (5.7%) animals recovered from acute GVH disease, while all controls died. Indralin treatment after irradiation resulted in a 30% increase in survival of exposed mice. Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 146, No. 11, pp. 507–511, November, 2008     

Cell-Mediated Immune Responses of Preleukemic AKR Mice

Splenic lymphocytes from preleukemic AKR mice are capable of participating in various cell-mediated immune responses. Spleen cells from AKR mice aged 1 to 10 months produced a significant graft-versus-host reaction when injected into 8-day-old AKR × C57Bl/6 F₁ hybrids. Splenic lymphocytes from similarly aged mice were also capable of responding to allogenic stimulation in a mixed lymphocyte reaction. AKR mice aged 1 to 10 months developed a contact sensitivity response to picryl chloride. It was concluded that mice of this high-leukemic strain have a competent cell-mediated immune system and there is no depression of immunity during the preleukemic period.     

Effects of delta-sleep-inducing peptide on NMDA-induced convulsive activity in rats

Acute experiments on rats showed that the ED₁₀₀ of NMDA for induction of clonic convulsions was 0.53 μg, while the ED₁₀₀ of NMDA for inducing tonic extension of the forelimbs was 5.02 μg/animal. Determination of these parameters after administration of delta-sleep-inducing peptide (100 μg/kg, i.p.) revealed 2.3- and 4.46-fold increases. These results provide evidence for a neuroprotective role of delta-sleep-inducing peptide in relation to excitatory amino acid receptor agonists. Department of Normal Physiology, State Medical University, 2 Valikhovskii Lane, 270100 Odessa, Ukraine. Translated from Rossiiskii Fiziologicheskii Zhurnal imeni I. M. Sechenova, Vol. 83, No. 9, pp. 32–36, September, 1997.     

Dynorphin administered to Newborn rats modulates morphogenesis of the heart

Proliferation, activity of the nucleolar organizer region, and protein content in cardiomyocytes were studied in 21-day-old rats intraperitoneally treated with κ-opioid receptor agonist dynorphin A_1–13 in a dose of 100 μg/kg on postnatal days 2–6. The content of catecholamines in the heart and proliferative activity of cardiomyocytes remained unaffected, but the number of nucleoli in cardiomyocyte nuclei and the integral optical density of cardiomyocytes stained with amido black B (protein content) increased. The data suggest that administration of dynorphin to newborn rats considerably modulates morphogenesis of the heart at later terms. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 129, No. 6, pp. 623–625, June, 2000     

Effect of hyperlipidemia on thymocyte sensitivity to apoptosis in CBA and C57Bl/6 mice

Effects of experimental hyperlipidemia on apoptosis and proliferation of thymocytes in response to mitogens were studied in CBA and C57Bl/6 mice. The concentrations of cholesterol in the serum and thymocyte membranes increased in both mouse strains. Spontaneous and dexamethasone-induced apoptosisin vitro and the proliferative response to phytohemagglutinin and concanavalin A were enhanced in thymocytes from C57Bl/6 mice and suppressed in cells from CBA mice. These data suggest opposite reactions of thymocyte to increased serum cholesterol concentration in these two strains, associated with stimulation and suppression of cell activity. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 130, No. 8, pp. 200–202, August, 2000     

Effects of Selank on behavioral reactions and activities of plasma enkephalin-degrading enzymes in mice with different phenotypes of emotional and stress reactions

Comparative study of plasma activities of enkephalin-degrading enzymes in mice with different phenotypes of emotional and stress reactions revealed significant differences between intact BALB/c and C57Bl/6 mice by the half-life of plasma leu-enkephalin. Selank in a dose of 100 /kg produced an anxiolytic effect in the open-field test and increased the half-life of plasma leu-enkephalin in BALB/c mice, but had no effect on behavioral reactions and enkephalinase activities in C57Bl/6 mice. Our results suggest that anxiolytic activity of Selank is associated with inhibition of enkephalin-degrading enzymes.