Violacein Treatment Modulates Acute and Chronic Inflammation through the Suppression of Cytokine Production and Induction of Regulatory T Cells.

Inflammation is a necessary process to control infection. However, exacerbated inflammation, acute or chronic, promotes deleterious effects in the organism. Violacein (viola), a quorum sensing metabolite from the Gram-negative bacterium Chromobacterium violaceum, has been shown to protect mice from malaria and to have beneficial effects on tumors. However, it is not known whether this drug possesses anti-inflammatory activity. In this study, we investigated whether viola administration is able to reduce acute and chronic autoimmune inflammation. For that purpose, C57BL/6 mice were intraperitoneally injected with 1 µg of LPS and were treated with viola (3.5mg/kg) via i.p. at the same time-point. Three hours later, the levels of inflammatory cytokines in the sera and phenotypical characterization of leukocytes were determined. Mice treated with viola presented a significant reduction in the production of inflammatory cytokines compared with untreated mice. Interestingly, although viola is a compound derived from bacteria, it did not induce inflammation upon administration to naïve mice. To test whether viola would protect mice from an autoimmune inflammation, Experimental Autoimmune Encephalomyelitis (EAE)-inflicted mice were given viola i.p. at disease onset, at the 10th day from immunization. Viola-treated mice developed mild EAE disease in contrast with placebo-treated mice. The frequencies of dendritic cells and macrophages were unaltered in EAE mice treated with viola. However, the sole administration of viola augmented the levels of splenic regulatory T cells (CD4+Foxp3+). We also found that adoptive transfer of viola-elicited regulatory T cells significantly reduced EAE. Our study shows, for the first time, that violacein is able to modulate acute and chronic inflammation. Amelioration relied in suppression of cytokine production (in acute inflammation) and stimulation of regulatory T cells (in chronic inflammation). New studies must be conducted in order to assess the possible use of viola in therapeutic approaches in human autoimmune diseases.

Effect of high intensity aerobic exercise and mesterolone on remodeling of Achilles tendon of C57BL/6 transgenic mice.

The effect of mesterolone and intensive treadmill training (6 weeks, 5 days/week, means: 15.82 m/min and 45.8 min/day) in Achilles tendon remodeling was evaluated. Sedentary mice treated with mesterolone (Sed-M) or vehicle (Sed-C, placebo/control) and corresponding exercised (Ex-M and Ex-C) were examined. SDS-polyacrylamide gel electrophoresis was used for determining collagen bands and hydroxyproline concentration. Collagen fibril diameter, the area and number of fibrils contained in an area probe, and the ultrastructure of fibroblasts (tenocytes) were determined. The presence of collagen was notable in the tendons of all groups. Collagen alpha(1/)alpha(2) bands in Sed-M, Ex-C, and Ex-M were higher than in Sed-C, as shown by hydroxyproline content, but collagen beta-chain appeared only in Ex-C. Noticeable bands of non-collagenous proteins were found in Sed-M and Ex-M. The number of fibrils in the area probe increased markedly in Sed-M and Ex-C (12-fold), but their diameter and area were unchanged compared with Sed-C. In Ex-M, the fibril number decreased by three-fold to 3.5-fold compared with Sed-M and Ex-C, whereas diameter and area increased. Sed-C tenocytes appeared quiescent, whereas those in the other groups seemed to be engaged in protein synthesis. The density of tenocytes was smaller in Sed-C than in Ex-C, Sed-M, and Ex-M. Thus, mechanical stimuli and mesterolone alter the morphology of tenocytes and the composition of the tendon, probably through fibrillogenesis and/or increased intermolecular cross-links. The ergogenic effect is evidenced by the activation of collagenous and non-collagenous protein synthesis and the increase in the diameter and area of collagen fibrils. This study might be relevant to clinical sports medicine.

Inhibition of caudal fin actinotrichia regeneration by acetylsalicylic acid (aspirin) in teleosts

Various substances have been used to investigate physiological and physiophatological processes in animals. In this study, we investigated the effects of acetylsalicylic acid (ASA, aspirin) on the regeneration of actinotrichia, skeletal structures of the caudal fin of teleosts. Two groups of fish (Tilapia rendalli) were maintained in aquaria with dechlorinated water at 24 graus Celsius, with one group being exposed to ASA (0.1 g/l) for 24 h. Thereafter ASA-treated and untreated (control) fishes were anesthetized and their tail fin amputated. After periods ranging from 4-12 days, the fishes were sacrified and the regeneration tissue was processed for light and transmission electron microscopy and picrosirius-hematoxylin staining. Control specimens ahowed normal regeneration of the actinotrichia, whereas all (except one) of the ASA-treated fishes showed no regeneration. The 20 ASA-treated fishes devoid of actinotrichia had varying degrees pf caudal fin regeneration. These results indicate that, as in mammal, aspirin also affects biological processes in fish. Based on reports in the literature, we hypothesize that ASA interfered with the transcripition of the fibroblast genes necessary for the synthesis of elasoidin, or altered the typical rapid turn-over of this protein, thereby affecting regeneration could be a valuable approach for instigating cell-matrix interactions. This model could also be useful for evaluating the toxic effects of river pollution and chemical damping.