Impact of gold nanoparticles (AuNPs) in human neutrophils in vitro and in leukocytes attraction in vivo: A sex-based analysis

Some differences exist between the male and female immune systems. Despite this, a sex-based analysis is not frequently performed in most studies. Knowing that inflammation is a common undesired effect observed resulting from nanoparticle (NP) exposure, we investigate here how gold NPs with a primary size of 20 (AuNP20) and 70 nm (AuNP70) will alter the biology of polymorphonuclear neutrophil cells (PMNs) isolated from men and women as well as their potential pro-inflammatory effect in vivo in male and female mice. We found that AuNP20 significantly delay apoptosis only in PMN isolated from men. The production of interleukin (IL)- 8 by PMNs was increased by both AuNPs regardless of sex although significance was only observed in AuNP20-induced PMNs. Using the murine air pouch model of inflammation, AuNPs did not induce a neutrophilic infiltration regardless of sex. In conclusion, AuNPs could differently alter the biology of PMNs according to sex.

Methanolic extract of Cariniana rubra Gardner ex Miers stem bark negatively regulate the leukocyte migration and TNF-α and up-regulate the annexin-A1 expression

ETHNOPHARMACOLOGICAL RELEVANCE

Cariniana rubra Gardner ex Miers (Lecythidaceae), is a native and endemic tree in Brazil, whose inner stem bark decoction preparation is used in folk medicine to treat various inflammatory disorders. Previous scientific reports confirmed its popular use as an anti-inflammatory, without, however, evaluating its action mechanisms.

AIM

The objective of this study was to determine the cytotoxicity and anti-inflammatory mechanism of action of the methanolic extract of Cariniana rubra (MECr), using experimental models in vivo and in vitro, as well as to identify secondary metabolites present in the extract.

MATERIAL AND METHODS

The MECr was prepared by maceration of inner stem bark powder in methanol (1:10 w/v). The in vitro cytotoxicity effect was evaluated in CHO-k1 cells. The Hippocratic screening test was conducted to evaluate the acute toxicity of MECr in mice. The actions of MECr on leukocyte migration, cytokine levels (IL-1β and TNF-α) and annexin-A1 (AnxA1) expression, were carried out on lambda-type carrageenan air pouch inflammation model in Swiss mice. Additionally, the phytochemical analysis of MECr was carried out by thin-layer chromatography (TLC) and spectrometric mass analysis with electrospray ionization ESI(-)/MS and gas chromatography-mass spectrometry (GC-MS).

RESULTS

Treatment of CHO-k1 cells for 24 h with MECr did not cause cytotoxicity (IC₅₀ > 200 μg/mL), however, the MECr was shown to be cytotoxic after 72 h of cell exposure (IC₅₀ = 19.90 ± 3.51 μg/mL). In the Hippocratic test, oral treatment of mice with 750, 1500, or 3000 mg/kg of MECr did not show any histopathological changes and mortality during the 14 days of observation. In the carrageenan air pouch inflammation model, MECr reduced (p < 0.001) polymorphonuclear migration (57.7% and 57.8%), leukocyte monocyte migration (74.5% and 61.8%) in the air pouch cavity and in the skin tissue, respectively. MECr also inhibited TNF-α concentration in the air cavity wash (3.2%, p < 0.01) and increased expression of the AnxA1 protein (26.9%, p < 0.01) in the skin tissue, particularly in neutrophils. β-sitosterol (1.95%), gallic acid (1.24%), β-amyrin (0.87%) and stigmasterol (0.66%) were identified as the major constituents in methanolic extract.

CONCLUSION

MECr exhibits significant anti-inflammatory action at least by increasing AnxA1 expression and by inhibiting the release of TNF-α pro-inflammatory cytokine and leukocyte migration, which is probably linked to the presence of identified biologically active compounds, especially gallic acid and terpenes. We believe that the results of this study provide a pharmacological basis for the MECr to be considered as a potential therapeutic agent for the treatment of inflammatory diseases.

In vitro and in vivo anti-inflammatory activity and chemical composition of Renealmia petasites Gagnep

The study aimed to investigate the chemical composition and the anti-inflammatory activity of the hydroethanolic rhizomes, stems, and leaf extracts of Renealmia petasites using in vitro and in vivo assays. The chemical composition of the extracts was characterized in a linear iron trap mass spectrometer. Total phenolic, flavonoid, and tannin content were determined by spectrophotometry analyses. In vitro anti-inflammatory activity was investigated in lipopolysaccharide-stimulated macrophages evaluating the influence on the production of superoxide anion (O₂^-), nitric oxide (NO), and the pro-inflammatory cytokines tumor necrosis factor (TNF-α) and interleukin-6 (IL-6). In vivo effects were determined using the air pouch model in which were inoculated carrageenan and thereafter treated with 50 mg/kg of the hydroethanolic extracts of R. petasites. After 4 and 24 h, the cellular influx, protein exudation, cytokines, and nitric oxide were evaluated. Eight compounds were tentatively identified in the R. petasites extracts, suggesting five diarylheptanoids, one flavonoid, and two fatty alcohols. The in vitro results showed that the extracts were capable of blocking free radicals and/or inhibiting their intracellular actions by inhibiting the production of important mediators of the inflammatory process, such as NO, O₂^-, TNF-α, and IL-6. In vivo, R. petasites significantly decrease the influx of leukocytes, mainly neutrophils, protein exudation, NO, TNF-α, and IL-6 concentration in the air pouch model. The results evidenced that R. petasites can be considered a promising alternative therapy for the treatment and management of osteoarthritis and other inflammatory diseases.

Protective effect of the intravenous anesthetic propofol against a local inflammation in the mouse carrageenan-induced air pouch model

Aim: 2,6-Di-isopropylphenol (propofol) is an intravenous general anesthetic widely used in the operating room for general anesthesia and in the intensive care unit for sedation. The mouse air pouch model is versatile in studying the anti-inflammatory effect of a drug on a local inflammation, which is induced by a variety of substances. In this study, using the carrageenan-induced air pouch inflammation model, we tested whether propofol mitigates inflammation occurring locally in the mouse air pouch. Methods: Carrageenan-induced air pouch inflammation model. Results: Propofol inhibited the production of tumor necrosis factor (TNF)-α and interleukin (IL)-6 in the pouch. Propofol also inhibited the production of neutrophil chemokines, KC and MIP-2, and decreased the number of both Ly-6G⁺/CD11b⁺ cells (assumed to be primarily neutrophils) and Ly-6G^-/CD11b⁺ cells (assumed to be monocytes/macrophages), recruited into the pouch at 3 h after injection of carrageenan. Conclusion: Propofol has an anti-inflammatory property in the carrageenan-induced mouse air pouch local inflammation model, by inhibiting the production of pro-inflammatory cytokines (TNF-α and IL-6), as well as by inhibiting the production of chemokines (KC and MIP-2), which might be associated with the inhibition of intra-pouch recruitment of white blood cells.

Anti-inflammatory and anti-angiogenesis effect of bee pollen methanolic extract using air pouch model of inflammation

BACKGROUND AND PURPOSE

Research on new drugs with a natural source and low side effects is a priority in pharmacology studies. The present study was conducted to investigate the anti-inflammatory and anti-angiogenesis effects of bee pollen extract in the air pouch model of inflammation.

EXPERIMENTAL APPROACH

To achieve this goal, male rats were moderately anesthetized and then 20 and 10 mL of sterile air were subcutaneously injected into the intrascapular area of the back of the rat on first and third days, respectively. On day 6, inflammation was induced by intrapouch injection of carrageenan. Normal saline in the control group and bee pollen methanolic extract (50, 100, and 200 mg/pouch) were administered at day 6, simultaneously with carrageenan, and then for 2 consecutive days only normal saline and the extracts were injected. Following sacrificing the rats the pouch was opened and the exudate volume, leukocyte accumulation, granulation tissue weight, vascular endothelial growth factor (VEGF), interleukin 1beta, and tumor necrosis factor alpha (TNF-α) concentrations were determined 3 days after induction of inflammation. In order to investigate the angiogenesis, the granulation tissue was removed, homogenized in the Drabkin's reagent, and then centrifuged. The supernatant was filtered and the hemoglobin concentration was determined using a spectrophotometer.

RESULTS

Bee pollen extract significantly decreased the exudate volume, leukocyte accumulation, granulation tissue weight, angiogenesis, VEGF, and TNF-α concentration.

CONCLUSION AND IMPLICATIONS

The findings of the current study revealed that bee pollen methanolic extract has an anti-inflammatory and anti-angiogenesis effect, which could be attributed to the inhibition of VEGF and TNF-α production in the inflammatory exudates.

Effects of salbutamol on the inflammatory parameters and angiogenesis in the rat air pouch model of inflammation

In the present study, effects of salbutamol on the inflammatory parameters, angiogenesis, interleukin-1 beta (IL-1β) and vascular endothelial growth factor (VEGF) levels were investigated in an air pouch model of inflammation. Inflammation was induced by intrapouch administration of 1% solution of sterile carrageenan in male Wistar rats. Salbutamol (125, 250 and 500 µg/rat) and salbutamol (500 µg/rat) plus propranolol (100 μg/rat) were injected intrapouch. After 6 and 72 h, fluid inside the pouches was collected to measure volume of exudates, leukocytes number and IL-1β levels. To determine angiogenesis, the granulation tissues were dissected out and weighed 3 days after carrageenan injection, then hemoglobin concentration was assessed using a hemoglobin assay kit. In addition, amount of VEGF in the exudates was measured 72 h after induction of inflammation. Leukocyte accumulation and the volume of exudates were significantly inhibited by salbutamol administration. In addition, salbutamol decreased the production of VEGF and IL-1β. Moreover, all used doses of salbutamol significantly inhibited angiogenesis. Interestingly, effects of salbutamol on the attenuation of angiogenesis and inflammatory parameters was similar to diclofenac sodium. Co-administration of propranolol with salbutamol clearly reversed anti-inflammatory effects of salbutamol. Salbutamol can decrease acute and chronic inflammation by β₂-adrenergic receptors activation. The observed IL-1β and VEGF inhibitory properties of salbutamol may be responsible for anti-inflammatory and anti-angiogenic effect of the agent.

The Role of Chemokine and Glycosaminoglycan Interaction in Chemokine-Mediated Migration In Vitro and In Vivo

Chemokines have a range of functions, including the activation and promotion of the vectorial migration of leukocytes. They mediate their biological effects by binding to their cognate G-protein-coupled receptors. Upon activation of the heterotrimeric G proteins, the Gα subunit exchanges GDP for GTP and dissociates from the receptor and from the Gβγ subunits, and both G-protein complexes go on to activate other downstream signaling events. In addition, chemokines interact with cell-surface glycosaminoglycans (GAGs). This potential for binding GAG components of proteoglycans on the cell surface or within the extracellular matrix allows the formation of the stable chemokine gradients necessary for leukocyte chemotaxis. In this chapter, we describe techniques for studying chemotaxis both in vivo and in vitro, as well as the creation of chemokine receptor-expressing cell lines, in order to examine this process in isolation.