Prostaglandins mediate zymosan-induced sickness behavior in mice

Leptin reduces LPS-induced A1 reactive astrocyte activation and inflammation via inhibiting p38-MAPK signaling pathway

Neurotoxic A1 reactive astrocytes are induced by inflammatory stimuli. Leptin has been confirmed to have neuroprotective properties. However, its effect on the activation of A1 astrocytes in infectious inflammation is unclear. In the current study, astrocytes cultured from postnatal day 1 Sprague-Dawley rats were stimulated with lipopolysaccharide (LPS) to induce an acute in vitro inflammatory response. Leptin was applied 6 h later to observe its protective effects. The viability of the astrocytes was assessed. A1 astrocyte activation was determined by analyzing the gene expression of C3, H2-D1, H2-T23, and Serping 1 and secretion of pro-inflammatory cytokines IL-6 and TNF-α. The levels of phospho-p38 (pp38) and nuclear factor-κB (NF-κB) phosphor-p65 (pp65) were measured to explore the possible signaling pathways. Additionally, an LPS-induced inflammatory animal model was established to investigate the in vivo effects of leptin on A1 astrocytic activation. Results showed that in the in vitro culture system, LPS stimulation caused elevated expression of A1 astrocyte-specific genes and the secretion of pro-inflammatory cytokines, indicating the activation of A1 astrocytes. Leptin treatment significantly reversed the LPS induced upregulation in a dose-dependent manner. Similarly, LPS upregulated pp38, NF-κB pp65 protein and inflammatory cytokines were successfully reduced by leptin. In the LPS-induced animal model, the amelioratory effect of leptin on A1 astrocyte activation and inflammation was further confirmed, showed by the reduced sickness behaviors, A1 astrocyte genesis and inflammatory cytokines in vivo. Our results demonstrate that leptin efficiently inhibits LPS-induced neurotoxic activation of A1 astrocytes and neuroinflammation by suppressing p38-MAPK signaling pathway.

Possible role of corticosterone on behavioral, physiological, and immune responses in chicks

Glucocorticoids are one of steroid hormone and have a variety of functions including stress response, carbohydrate metabolism, and modulation of immune system in vertebrates. Corticosterone is the main glucocorticoid in birds, although the precise role of the glucocorticoid during immune challenge is not fully understood. Therefore, the purpose of the present study was to determine if a single subcutaneous injection of corticosterone could affect inflammation-related gene expressions in the spleen and liver of chicks (Gallus gallus). In addition, the effects of corticosterone injection on the food intake, cloacal temperature, formation of conditioned visual aversion, and plasma constituents were also measured. Corticosterone did not affect the food intake or cloacal temperature and did not cause conditioned visual aversion in chicks. The corticosterone injection was associated with a significant decrease in gene expression of several pro-inflammatory cytokines including inducible nitric oxide synthase and cyclooxygenase-2 in the spleen and liver at 1 and 3 h post-injection. Corticosterone increased the plasma glucose and uric acid concentrations and the antioxidant capacity. In summary, the present study suggests that corticosterone is likely not associated with food intake, cloacal temperature or the development of aversive sensation, but suppresses the synthesis of inflammation-associated bioactive molecules and increases the antioxidant capacity in chicks.

Evaluation of the antiedematogenic and anti-inflammatory properties of Ximenia americana L. (Olacaceae) bark extract in experimental models of inflammation

Edema is one of the obvious indicators of inflammation and a crucial factor to take into account when assessing a substance's capacity to reduce inflammation. We aimed to evaluate the antiedematogenic and anti-inflammatory profile of the hydroethanolic barks extract of Ximenia americana (HEXA). The possible antiedematogenic and anti-inflammatory effect of EHXA (50, 100 mg/kg and 250 mg/kg v.o) was evaluated using the paw edema induced by carrageenan, zymosan, dextran, CFA and by different agents inflammatory (serotonin, histamine, arachidonic acid and PGE2), and pleurisy model induced by carrageenan and its action on IL-1β and TNF-α levels was also evaluated. HEXA demonstrated a significant antiedematogenic effect at concentrations of 50, 100 and 250 mg/kg on paw edema induced by carrageenan, zymosan and dextran. However, the concentration of 50 mg/kg as standard, demonstrating the effect in the subchronic model, induced CFA with inhibition of 59.06 %. In models of histamine-induced paw edema, HEXA showed inhibition of - 30 min: 40.49 %, 60 min: 44.70 % and 90 min: 48.98 %; serotonin inhibition - 30 min: 57.09 %, 60 min: 66.04 % and 90 min: 61.79 %; arachidonic acid inhibition - 15 min: 36.54 %, 30 min: 51.10 %, 45 min: 50.32 % and 60 min: 76.17 %; and PGE2 inhibition - 15 min: 67.78 %, 30 min: 62.30 %, 45 min: 54.25 % and 60 min: 47.92 %. HEXA significantly reduced (p < 0.01) leukocyte migration in the pleurisy model and reduced TNF-α and IL-1β levels in pleural lavage (p < 0.0001). The results showed that HEXA has the potential to have an antiedematogenic impact in both acute and chronic inflammation processes, with a putative mode of action including the suppression or regulation of inflammatory mediators.

Detailed Characterization of Brain Dysfunction in a Long-Term Rodent Model of Critical Illness

Critical illness encompasses a wide spectrum of life-threatening clinical conditions requiring intensive care. Our objective was to evaluate cognitive, inflammatory and cellular metabolism alterations in the central nervous system in an animal model of critical illness induced by zymosan. For this Wistar rats that were divided into Sham and zymosan. Zymozan was administered once intraperitoneally (30 g/100 g body weight) diluted in mineral oil. The animals were submitted to behavioral tests of octagonal maze, inhibitory avoidance and elevated plus maze. Brain structures (cortex, prefrontal and hippocampus) were removed at 24 h, 4, 7 and 15 days after zymosan administration for analysis of cytokine levels (TNF-α, IL-1b, IL-6 and IL-10), oxidative damage and oxygen consumption. Zymosan-treated animals presented mild cognitive impairment both in aversive (inhibitory avoidance) and non-aversive (octagonal maze) tasks by day 15. However, they did not show increase in anxiety (elevated-plus maze). The first neurochemical alteration found was an increase in brain pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α) at day 4th in the hippocampus. In cortex, a late (7 and 15 days) increase in TNF-α was also noted, while the anti-inflammatory cytokine IL-10 decrease from 4 to 15 days. Oxygen consumption was decreased in the hippocampus and pre-frontal, but not cortex, only at 7 days. Additionally, it was observed a late (15 days) increase in oxidative damage parameters. This characterization of brain dysfunction in rodent model of critical illness reproduces some of the alterations reported in humans such neuropsychiatric disorders, especially depression, memory loss and cognitive changes and can add to the nowadays used models.

Interleukin-1β and cathepsin D modulate formation of the terminal complement complex in cultured human disc tissue

PURPOSE

Formation of terminal complement complex (TCC), a downstream complement system activation product inducing inflammatory processes and cell lysis, has been identified in degenerated discs. However, it remains unclear which molecular factors regulate complement activation during disc degeneration (DD). This study investigated a possible involvement of the pro-inflammatory cytokine interleukin-1β (IL-1β) and the lysosomal protease cathepsin D (CTSD).

METHODS

Disc biopsies were collected from patients suffering from DD (n = 43) and adolescent idiopathic scoliosis (AIS, n = 13). Standardized tissue punches and isolated cells from nucleus pulposus (NP), annulus fibrosus (AF) and endplate (EP) were stimulated with 5% human serum (HS) alone or in combination with IL-1β, CTSD or zymosan. TCC formation and modulation by the complement regulatory proteins CD46, CD55 and CD59 were analysed.

RESULTS

In DD tissue cultures, IL-1β stimulation decreased the percentage of TCC + cells in AF and EP (P < 0.05), whereas CTSD stimulation significantly increased TCC deposition in NP (P < 0.01) and zymosan in EP (P < 0.05). Overall, the expression of CD46, CD55 and CD59 significantly increased in all isolated cells during culture (P < 0.05). Moreover, cellular TCC deposition was HS concentration dependent but unaffected by IL-1β, CTSD or zymosan.

CONCLUSION

These results suggest a functional relevance of IL-1β and CTSD in modulating TCC formation in DD, with differences between tissue regions. Although strong TCC deposition may represent a degeneration-associated event, IL-1β may inhibit it. In contrast, TCC formation was shown to be triggered by CTSD, indicating a multifunctional involvement in disc pathophysiology.

A single intra-articular dose of vitamin D analog calcipotriol alleviates synovitis without adverse effects in rats

1,25-dihydroxyvitamin-D3 and its derivatives have shown anti-arthritic and chondroprotective effects in experimental animal models with prophylactic dosing. The purpose of this preliminary study was to test the efficacy and safety of calcipotriol, vitamin D analog, as a treatment for a fully-developed knee arthritis in Zymosan-induced arthritis (ZIA) model. Forty 5-month-old male Sprague-Dawley rats were randomized into three arthritis groups and a non-arthritic control group with no injections (10 rats/group). A day after Zymosan (0.1 mg) had been administrated into the right knee joints, the same knees were injected with calcipotriol (0.1 mg/kg), dexamethasone (0.1 mg/kg) or vehicle in a 100 μl volume. The left control knees were injected with saline (PBS) on two consecutive days. All injections, blood sampling and measurements were performed under general anesthesia on days 0, 1, 3 and 8. Internal organs and knees were harvested on day 8 and the histology of the whole knees was assessed blinded. Joints treated with calcipotriol showed a milder histological synovitis than those treated with vehicle (p = 0.041), but there was no statistically significant difference between the dexamethasone and vehicle groups. The clinical severity of arthritis did not differ between the arthritis groups measured by body temperature, swelling of the knee, thermal imaging, clinical scoring or cytokine levels on days 1, 3 and 8. Weight loss was bigger in rats treated with dexamethasone, propably due to loss of appetite,compared to other arthritis groups on days 2-3 (p<0.05). Study drugs did not influence serum calcium ion and glucose levels. Taken together, this preliminary study shows that a single intra-articular injection of calcipotriol reduces histological grade of synovitis a week after the local injection, but dexamethasone did not differ from the vehicle. Calcipotriol may have an early disease-modifying effect in the rat ZIA model without obvious side effects.

Polysaccaride-rich extract of Caesalpina ferrea stem barks attenuates mice acute inflammation induced by zymosan: Oxidative stress modulation

ETHNOPHARMACOLOGICAL RELEVANCE

Stem barks of Caesalpinia ferrea Mart. Ex Tul. (Caesalpiniaceae), also known as pau-ferro jucá or jucaína, are popularly used to treat contusions, diabetes, rheumatism and other inflammatory conditions in the form of tea, lick or decoction.

OBJECTIVE

To evaluate the effect of the polysaccharide-rich extract obtained from C. ferrea stem barks (PE-Cf) in mice models of acute inflammation induced by zymosan and the involvement of oxidative stress biomarkers.

MATERIALS AND METHODS

Mice were treated with PE-Cf (0.001, 0.01, 0.1, 1 mg/kg) by endovenous route (i.v.) or per oral (p.o.) 30 or 60 min before injection of the inflammatory stimuli zymosan (0.5 mg; intraperitoneal or subcutaneous intraplantar). The inflammatory parameters (edema, nociception, leukocyte migration) and oxidative stress markers (myeloperoxidase-MPO, malondialdehyde-MDA, nitrite, reduced glutathione-GSH, glutathione peroxidase-GPx) were evaluated in the models of paw edema (hidropletysmometry/expressed as ml or area under curve-AUC) and peritonitis (optical microscopy/expressed as n° of cells/mm³ of peritoneal fluid). Statistical analysis was performed by ANOVA, followed by Bonferroni test.

RESULTS

PE-Cf (0.1, 0.01 and 1 mg/kg) dose-dependently inhibited paw edema, showing maximal effect (74%) at 1 mg/kg in the 5th (52 ± 9.6 μl vs. zymosan: 204 ± 3.6 μl). PE-Cf (1 mg/kg) also inhibited by 43% MPO activity in the paw tissues (17 ± 1 vs. zymosan: 30 ± 2.6 U/mg). Besides, 4 h after peritonitis induction, PE-Cf (1 mg/kg) reduced neutrophil migration by 84% (432 ± 45 vs. zymosan: 2651 ± 643 cells/mm³); visceral nociception by 76% (3 ± 0.6 vs. zymosan: 16 ± 4 writhes); nitric oxide by 73% (0.131 ± 0.033 vs. zymosan: 0.578 ± 0.185 NO_2^-/NO_3^-ml); MDA (98 ± 10 vs. zymosan:156 ± 21 U/ml), and increased GSH by 65% (736 ± 65 vs. zymosan: 259 ± 58 μmol/ml) and GPx by 72% (0.037 ± 0.007 vs. zymosan: 0.010 ± 0.005 U/mg protein).

CONCLUSION

The polysaccharide-rich extract of Caesalpinia ferrea stem barks present anti-inflammatory and antioxidant effects in mice models of acute inflammation induced by zymosan.

Prostate-to-bladder cross-sensitization in a model of zymosan-induced chronic pelvic pain syndrome in rats

BACKGROUND

The aim of the present study was to investigate the effects of chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) on bladder function and pathophysiology.

METHODS

To create a model for CPPS, rats were intraprostatically injected with zymosan or saline, serving as control. Metabolic cage experiments were performed 7, 14, or 21 days after zymosan injection and after 14 days in the control group. Thereafter, cystometry was performed in which simulated micturition cycles were induced by saline infusion and contractile responses to the cholinergic agonist methacholine and the purinergic agonist ATP were measured. Following cystometry, the prostate and urinary bladder were excised and assessed histopathologically for possible inflammatory changes.

RESULTS

Metabolic cage data revealed a significantly increased urinary frequency in zymosan treated rats. Likewise, the volume per micturition was significantly lower in all CPPS groups compared to controls. Cystometry showed a significant increase in the number of nonvoiding contractions, longer voiding time, and a trend towards lower compliance in CPPS rats compared to controls. Induction of CPPS led to significantly reduced cholinergic and purinergic contractile responses. Histopathological analysis demonstrated prostatic inflammation in all CPPS groups, in particular in later stage groups. Both the extent and grade of bladder inflammation were significantly higher in CPPS groups compared to controls.

CONCLUSIONS

The current findings demonstrate a potential prostate-to-bladder cross-sensitization leading to symptoms of bladder overactivity and signs of bladder inflammation. Future clinical studies are required to verify the outcomes of the current study and enable advancement of patient care.

Behavioral and physiological responses to intraperitoneal injection of zymosan in chicks

Zymosan is a cell wall component of the yeast Saccharomyces cerevisiae and produces severe inflammatory responses in mammals. When zymosan is peripherally injected in mammals, it induces several behavioral and physiological changes including anorexia and hyperthermia. However, to our knowledge, behavioral and physiological responses to zymosan have not yet been clarified in birds. Therefore, the purpose of the present study was to determine if intraperitoneal injection of zymosan affects food intake, voluntary activity, cloacal temperature, plasma corticosterone (CORT) and glucose concentrations, and splenic gene expression of cytokines in chicks (Gallus gallus). Intraperitoneal injection of zymosan (2.5 mg) significantly decreased food intake, voluntary activity, and plasma glucose concentration, and increased plasma CORT concentration. The injection of 0.5 mg zymosan significantly increased cloacal temperature, while 2.5 mg zymosan had a tendency to increase it. Finally, 2.5 mg zymosan significantly increased the splenic gene expression of interleukin-1β (IL-1β), IL-6, IL-8, interferon-γ, and tumor necrosis factor-like cytokine 1A. The present results suggest that zymosan would be one of components which induces nonspecific symptoms including anorexia, hypoactivity, hyperthermia, and stress responses, under fungus infection in chicks.

(E)-2-Cyano-3-(1H-Indol-3-yl)-N-Phenylacrylamide, a Hybrid Compound Derived from Indomethacin and Paracetamol: Design, Synthesis and Evaluation of the Anti-Inflammatory Potential

The compound (E)-2-cyano-3-(1H-indol-3-yl)-N-phenylacrylamide (ICMD-01) was designed and developed based on the structures of clinically relevant drugs indomethacin and paracetamol through the molecular hybridization strategy. This derivative was obtained by an amidation reaction between substituted anilines and ethyl 2-cyanoacetate followed by a Knoevenagel-type condensation reaction with indole aldehyde that resulted in both a viable synthesis and satisfactory yield. In order to assess the immunomodulatory and anti-inflammatory activity, in vitro assays were performed in J774 macrophages, and significant inhibitions (p < 0.05) of the production of nitrite and the production of cytokines (IL-1β and TNFα) in noncytotoxic concentrations were observed. The anti-inflammatory effect was also studied via CFA-induced paw edema in vivo tests and zymosan-induced peritonitis. In the paw edema assay, ICMD01 (50 mg kg-1) showed satisfactory activity, as did the group treated with dexamethasone, reducing edema in 2-6 h. In addition, there was no significant inhibition of PGE2, IL-1β or TNFα in vivo. Moreover, in the peritonitis assay that assesses leukocyte migration, ICMD-01 exhibited promising results. Therefore, these preliminary studies demonstrate this compound to be a strong candidate for an anti-inflammatory drug together with an improved gastrointestinal safety profile when compared to the conventional anti-inflammatory drugs.

Pyrogenic and neuroinflammatory properties of zymosan and its potential as an alternative to live yeast in antipyretic drug testing

Zymosan, an immunogenic cell wall extract of Saccharomyces cerevisiae has potential for use as an experimental pyrogen. However, the short-lived sickness responses noted with intraperitoneal and intra-articular administration of zymosan limits investigations on the long-term effectiveness of antipyretic drugs. Thus, there remains a need to establish an alternative route of zymosan administration that could induce long-lived fevers and inflammation. We injected male Sprague Dawley rats (250–300 g) subcutaneously with zymosan (30 or 300 mg/kg) or saline; n = 7–8. We measured core body temperature, cage activity, food intake and body mass for 24 h after injection. Blood and brain samples were collected at 2, 8, and 18 h after injection. Zymosan (300 mg/kg) induced fever, lethargy, and anorexia, which lasted for 24 h. Zymosan-induced sickness responses were accompanied by increased blood plasma levels of interleukin (IL)-6 and tumor necrosis factor (TNF)-α; activation of inflammatory transcription factors (nuclear factor (NF) for IL-6, signal transducer and activator of transcription (STAT)-3, and NF-κB) in the hypothalamus and circumventricular organs; and increased hypothalamic mRNA expression of TNF-α, IL-1β, and IL-6 and rate-limiting enzymes for prostaglandin synthesis. Our results confirm the suitability of subcutaneous administration of zymosan for screening antipyretic and anti-inflammatory drugs in rats.

Alpha lipoic acid and metformin alleviates experimentally induced insulin resistance and cognitive deficit by modulation of TLR2 signalling

BACKGROUND

Obesity is commonly found to be co-morbid with type 2 Diabetes Mellitus. In obese diabetic patients, TLR-2 receptor induced inflammation leads to the development of insulin resistance (IR). Furthermore, the IR is considered to be the most important cause for promoting cognitive decline which is evident in brain of patients with Alzheimer's disease related dementia (ADRD).

METHODS

In this study, the effect of α-lipoic acid (ALA) has been examined in rodent model of zymosan induced insulin resistance and cognitive deficits, targeting at TLR-2 signalling. TLR-2 agonist, Zymosan initiates inflammatory cascade, resulting in IR and cognitive dysfunction. Zymosan (50 mg/kg ip) was given to mice on 1st, 8th, 15th and 22nd day to induce IR which was confirmed by hyperglycaemia, hyperinsulinemia, hyperlipidimea, increased glycated haemoglobin and HOMA-IR. Further the cognitive performance was assessed in Morris water maze revealing cognitive deficit in zymosan treated mice.

RESULTS

Daily treatment with ALA for 28 days (50, 100, 200 mg/kg, ip) significantly improved insulin sensitivity and cognitive performance in mice by decreasing insulin resistance, corticosterone, IL-6 levels, acetylcholinesterase enzyme activity and oxidative stress in liver, cortex and hippocampus. ALA also increased adiponectin level and reduced body weight. Combination of ALA (100 mg/kg, ip) with metformin (100 mg/kg, ip) exhibited a potentiating effect in improving cognitive performance and insulin signalling.

CONCLUSION

The findings of the study supported the hypothesis that TLR-2 induced inflammation leads to insulin resistance and cognitive impairment and provides an evidence for the therapeutic effect of ALA in IR and ADRD patients.