RESUMO
ETHNOPHARMACOLOGICAL RELEVANCE: Cutaneous inflammatory diseases, such as irritant contact dermatitis, are usually treated with topical corticosteroids, which cause systemic and local adverse effects limiting their use. Thus, the discovery of new therapeutic alternatives able to effectively treat skin inflammatory disorders, without causing adverse effects, is urgently needed. AIM OF THE STUDY: To investigate the topical anti-inflammatory effect of oleic acid (OA), a monounsaturated fatty acid, into Pemulen® TR2-based semisolid dosage forms, employing a croton oil-induced irritant contact dermatitis model in mice. MATERIALS AND METHODS: Male Swiss mice were submitted to skin inflammation protocols by acute and repeated applications of croton oil. The anti-inflammatory activity of Pemulen® TR2 hydrogels containing OA was evaluated by assessing oedema, inflammatory cell infiltration, and pro-inflammatory cytokine IL-1ß levels. The mechanisms of action of OA were evaluated using cytokine IL-1ß application or pretreatment with the glucocorticoid antagonist mifepristone. Possible toxic effects of OA were also assessed. RESULTS: Pemulen® TR2 3% OA inhibited the acute ear oedema [maximal inhibition (Imax) = 76.41 ± 5.69%], similarly to dexamethasone (Imax = 84.94 ± 2.16%), and also inhibited ear oedema after repeated croton oil application with Imax = 85.75 ± 3.08%, similar to dexamethasone (Imax = 81.03 ± 4.66%) on the day 7 of the experiment. Croton oil increased myeloperoxidase activity, which was inhibited by Pemulen® TR2 3% OA (Imax = 71.37 ± 10.97%) and by 0.5% dexamethasone (Imax = 96.31 ± 3.73%). Pemulen® TR2 3% OA also prevented the increase in pro-inflammatory cytokine IL-1ß levels induced by croton oil (Imax = 94.18 ± 12.03%), similar to 0.5% dexamethasone (Imax = 87.21 ± 10.58%). Besides, both Pemulen® TR2 3% OA and 0.5% dexamethasone inhibited IL-1ß-induced ear oedema with an Imax of 80.58 ± 2.45% and 77.46 ± 1.92%, respectively. OA and dexamethasone anti-inflammatory effects were prevented by 100% and 91.43 ± 5.43%, respectively, after pretreatment with mifepristone. No adverse effects were related to Pemulen® TR2 3% OA administration. CONCLUSIONS: OA demonstrated anti-inflammatory efficacy similar to dexamethasone, clinically used to treat skin inflammatory conditions, without presenting adverse effects.
Assuntos
Anti-Inflamatórios/farmacologia , Dermatite Irritante/prevenção & controle , Ácido Oleico/farmacologia , Pele/efeitos dos fármacos , Administração Cutânea , Animais , Anti-Inflamatórios/administração & dosagem , Anti-Inflamatórios/toxicidade , Óleo de Cróton , Dermatite Irritante/etiologia , Dermatite Irritante/metabolismo , Dermatite Irritante/patologia , Modelos Animais de Doenças , Mediadores da Inflamação/metabolismo , Interleucina-1beta/metabolismo , Masculino , Camundongos , Ácido Oleico/administração & dosagem , Ácido Oleico/toxicidade , Pele/metabolismo , Pele/patologiaRESUMO
BACKGROUND: Statins represent a class of drugs that effectively lowers cholesterol, however they also possess pleiotropic effects, like promotion of angiogenesis, prevention of bone loss, immunomodulatory and anti-inflammatory effects. OBJECTIVES: Thus, the aim of this study was to investigate the activity of simvastatin topically applied in mice in acute and chronic skin inflammation models. METHODS: Skin inflammation was induced in mice ears by topical application of 12-O-tetradecanoylphorbol acetate (TPA). In the acute model, ear oedema was measured by the increase of ear thickness 6h after TPA (2.5µg/ear). The chronic inflammatory process was induced by multiple applications of TPA (2.0µg/ear) for nine alternate days, and the oedema was measured daily as the increase in ear thickness. RESULTS: Topical treatment was applied immediately after TPA in acute model or started at 5th day of chronic experiment. For acute model treatment was simvastatin (0.24, 0.71 and 2.40µM), dexamethasone (0.13µM), both in acetone or vehicle alone (acetone). In chronic model simvastatin (1% and 3%) and dexamethasone (0.5%) were incorporated in ointment preparations, and a group received ointment alone (vehicle). Samples of ear tissue (6mm) were taken from acute and chronic models, weighted and prepared for histological analysis and myeloperoxidase (MPO) enzymatic activity evaluation. Application of simvastatin in acetone reduced the ear oedema after a single TPA application in a dose dependent manner [ID(50) of 0.47 (0.22-1.13) µM], and the MPO enzymatic activity up to 61±10%. Also, both simvastatin ointment preparations 1% and 3% reduced acute TPA-induced ear oedema in 55±7% and 65±8%, respectively. In the chronic model, simvastatin ointment 1% was able to reduce ear oedema (25±3%) and ear weight (10±1%), though 3% formulation augmented both parameters. Histological analysis revealed a reduction of swelling and leukocyte migration in the acute model for both the formulations of simvastatin (1% and 3%), while in chronic model simvastatin 1% decreased ear swelling and epidermal thickness, but simvastatin 3% increased both parameters. CONCLUSION: The results confirm the anti-inflammatory activity of simvastatin when applied topically in both acute and chronic models of skin inflammation. Besides, the formulation of simvastatin ointment 1% shows to be a very effective formulation for a chronic usage.
Assuntos
Dermatite Irritante/tratamento farmacológico , Sinvastatina/administração & dosagem , Doença Aguda , Administração Tópica , Animais , Anti-Inflamatórios não Esteroides/administração & dosagem , Doença Crônica , Dermatite Irritante/etiologia , Dermatite Irritante/metabolismo , Dermatite Irritante/patologia , Modelos Animais de Doenças , Feminino , Camundongos , Pomadas , Peroxidase/metabolismo , Antígeno Nuclear de Célula em Proliferação/metabolismo , Acetato de Tetradecanoilforbol/administração & dosagem , Acetato de Tetradecanoilforbol/toxicidadeRESUMO
BACKGROUND: Expression of murine CCL21 by dermal lymphatic endothelial cells (LEC) has been demonstrated to be one of the most important steps in Langerhans cell emigration from skin. Previously, our group and others have found that this chemokine is up-regulated in different human inflammatory skin diseases mediated by diverse specific immune responses. This study was carried out to investigate the involvement of CCL21 in human skin after challenge with irritant agents responsible for inducing Irritant Contact Dermatitis (ICD). RESULTS: Eleven normal individuals were challenged with different chemical or physical irritants. Two patients with Allergic Contact Dermatitis (ACD) were also challenged with the relevant antigen in order to have a positive control for CCL21 expression. Macroscopic as well as microscopic responses were evaluated. We observed typical ICD responses with mostly mononuclear cells in perivascular areas, but a predominance of polymorphonuclear cells away from the inflamed blood vessels and in the epidermis at 24 hours. Immunohistochemical studies showed up-regulation of CCL21 by lymphatic endothelial cells in all the biopsies taken from ICD and ACD lesions compared to normal skin. Kinetic study at 10, 48, 96 and 168 hours after contact with a classical irritant (sodium lauryl sulphate) showed that the expression of CCL21 was increased in lymphatic vessels at 10 hours, peaked at 48 hours, and then gradually declined. There was a strong correlation between CCL21 expression and the macroscopic response (r = 0.69; p = 0.0008), but not between CCL21 and the number of infiltrating cells in the lesions. CONCLUSIONS: These results provide new evidence for the role of CCL21 in inflammatory processes. Since the up-regulation of this chemokine was observed in ICD and ACD, it is tempting to speculate that this mechanism operates independently of the type of dermal insult, facilitating the emigration of CCR7+ cells.