ROCK Inhibition Drives Resolution of Acute Inflammation by Enhancing Neutrophil Apoptosis.

Uncontrolled inflammation leads to tissue damage and it is central for the development of chronic inflammatory diseases and autoimmunity. An acute inflammatory response is finely regulated by the action of anti-inflammatory and pro-resolutive mediators, culminating in the resolution of inflammation and restoration of homeostasis. There are few studies investigating intracellular signaling pathways associated with the resolution of inflammation. Here, we investigate the role of Rho-associated kinase (ROCK), a serine/threonine kinase, in a model of self-resolving neutrophilic inflammatory. We show that ROCK activity, evaluated by P-MYPT-1 kinetics, was higher during the peak of lipopolysaccharide-induced neutrophil influx in the pleural cavity of mice. ROCK inhibition by treatment with Y-27632 decreased the accumulation of neutrophils in the pleural cavity and was associated with an increase in apoptotic events and efferocytosis, as evaluated by an in vivo assay. In a model of gout, treatment with Y-27632 reduced neutrophil accumulation, IL-1ß levels and hypernociception in the joint. These were associated with reduced MYPT and IκBα phosphorylation levels and increased apoptosis. Finally, inhibition of ROCK activity also induced apoptosis in human neutrophils and destabilized cytoskeleton, extending the observed effects to human cells. Taken together, these data show that inhibition of the ROCK pathway might represent a potential therapeutic target for neutrophilic inflammatory diseases.

Encapsulation of trans-aconitic acid in mucoadhesive microspheres prolongs the anti-inflammatory effect in LPS-induced acute arthritis.

trans-Aconitic acid (TAA) is the main constituent of the leaves from the medicinal plant Echinodorus grandiflorus, used to treat different inflammatory diseases. TAA induces a potent but short-lasting biological response, credited to its high polarity and unfavorable pharmacokinetics. Here we developed, characterized and evaluated the anti-inflammatory activity of mucoadhesive microspheres loaded with TAA. Seven batches of mucoadhesive microspheres were prepared by the emulsification/solvent evaporation method, employing different proportions of TAA and Carbopol 934 or/and hydroxypropylmethylcellulose. All batches were characterized for their particle medium size, polydispersity index and entrapment percentage. The batch coded F3c showed highest entrapment percentage and was characterized by infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analyses (TGA) and zeta potential. The anti-inflammatory activity of F3c was assessed in a model of acute arthritis induced by injection of LPS in the knee joint of Swiss mice. The granulometric analyses indicated heterogeneous size distribution for F3c. SEM characterization indicated microspheres with slightly irregular shape and rough surface. Results from ATR-FTIR and thermal analyses (DSC and TGA) pointed out absence of incompatibility between the components of the formulation; thermal events related to the constituents were isolated and randomly located, suggesting amorphous distribution of TAA in the formulation matrix. The zeta potential of the formulations varied from -30 to -34 mV, which may contribute to good stability. When given orally to mice, F3c induced a prolonged anti-inflammatory response by reducing total cell count and neutrophilic accumulation in the joint cavity even when given 48 and 36 h before the stimulus, respectively, in comparison to free TAA (up to 24 and 6 h, respectively). Therefore, the encapsulation of TAA in mucoadhesive microspheres provided its sustained release, indicating that this drug delivery system is a potential agent to treat inflammatory diseases by regulating cell influx.

In Vitro TNF-α Inhibitory Activity of Brazilian Plants and Anti-Inflammatory Effect of Stryphnodendron adstringens in an Acute Arthritis Model.

Stryphnodendron species, popularly named "barbatimão," are traditionally used in Brazil as anti-inflammatory agents. This study aimed to investigate the effect of barbatimão and 11 other species on the production of tumor necrosis factor-alpha (TNF-α) in lipopolysaccharide- (LPS-) stimulated THP-1 cells, as well as their anti-arthritis activity. The extracts of Stryphnodendron adstringens, Stryphnodendron obovatum, Campomanesia lineatifolia, and Terminalia glabrescens promoted a concentration-dependent inhibition of TNF-α. Mice injected with LPS in the knee joint were treated per os with fractions from the selected extracts. Both the organic (SAO) and the aqueous (SAA) fractions of S. adstringens promoted a dose-dependent reduction of leukocyte migration and neutrophil accumulation into the joint, but none of them reduced CXCL1 concentration in the periarticular tissue. In contrast, treatment with C. lineatifolia and T. glabrescens fractions did not ameliorate the inflammatory parameters. Analyses of SAO by Ultra Performance Liquid Chromatography (UPLC) coupled to electrospray ionization mass spectrometry (ESI-MS) led to the identification of gallic acid along with 11 prodelphinidins, characterized as monomers and dimers of the B-type. Our findings contribute to some extent to corroborating the traditional use of S. adstringens as an anti-inflammatory agent. This activity is probably related to a decrease of leukocyte migration into the inflammatory site. Polyphenols like gallic acid and prodelphinidins, identified in the active fraction, may contribute to the observed activity.