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Acta sci. vet. (Impr.); 41: Pub. 1168, 2013. tab, graf, ilus

Artigo em Inglês | VETINDEX | ID: biblio-1371083

Resumo

Background: Inflammation is an adaptive response that is triggered by noxious stimuli and conditions, which involves interactions amongst many cell types and mediators, and underlies many pathological process. Unsaturated fatty acids (UFAs) can infl uence inflammation through a variety of mechanisms, and have been indicated as alternative anti-inflammatory agents to treat several inflammatory skin disorders. Pumpkin seed oil (PSO) is rich in UFAs, but its topical anti-inflammatory properties have not been investigated. Therefore, the aim of this paper was to evaluate the effects of PSO on acute and chronic cutaneous inflammation experimental models. Materials, Methods & Results: PSO was purchased commercially and analyzed phytochemically. The topical anti-inflammatory activity of PSO at different concentrations was evaluated on acute models (xylene- and 12-O-tetradecanoylphorbol acetate (TPA)-induced ear edema) and chronic model (multiple applications of oxazolone-induced dermatitis) in mice. Indomethacin and dexamethasone were used as reference drugs. The ear swelling was measured in both ear thickness (µm) and weight tissue (mg) at 1 and 4 h after xylene and TPA application, respectively. In the chronic model, the effectiveness of treatments was measured each 24 h post-challenge with oxazolone for 4 days. At the end of experiments, ear biopsies were assessed by histological analysis on hematoxylin-eosin- and toluidine blue-stained slides. Data were submitted to ANOVA followed Student Newman Keuls test (P < 0.05). PSO was characterized by a high content of unsaturated fatty acids (UFAs) (79.80%), including linoleic acid (ω-6, 55.83%) and oleic acid (ω-9, 23.47%). PSO caused a dose-dependent inhibition of xylene and TPA-induced ear edema in both skin thickness and weight when compared to respective positive controls (P < 0.05). This anti-inflammatory effects was maximum when PSO was applied in nature (inhibition of 69.9 ± 2.8% and 78.1 ± 7.7% for inflammation induced by xylene and TPA, respectively; P < 0.05), and was similar to, at least, one drug reference (P < 0.05). In addition, the topical treatment with PSO caused the inhibition of inflammation-induced by oxazolone in 60.9 ± 9.8% when compared to control positive (P < 0.05), which was similar to dexamethasone (68.7 ± 8.1%, P < 0.05). In histological analysis, PSO reduced the inflammatory parameters (edema, congestion, epidermal hyperplasia and cellular infiltration) in inflammation models studied. However, the number of mastocytes in cell infiltration was reduced (17.6 ± 4.0) when compared to positive control (39.4 ± 5.8 cells) in chronic model (P < 0.05), but no differences were observed in acute models. Discussion: Topical anti-inflammatory activity of plant-originated substances can be evaluated in several experimental models. In this study, we used as phlogistic agents: xylene, a promoter of neurogenic inflammation; TPA, a phorbol ester that activate protein kinase C, leading to production of lipid-derived mediators; and oxazolone, an inductor of contact delayed-type hypersensitivity. Our results suggest that PSO alter inflammatory response via modulation of cellular and molecular mediators involved in inflammatory pathways activated by theses phlogistic agents. In addition, this oil was able to resolve a persistent inflammatory lesion similar to dexamethasone, but we did not observe any cutaneous alterations caused by its topical use as related for corticosteroids. This is the first report on topical anti-inflammatory potential of PSO in acute and chronic skin inflammation. This activity may be attributed the proper balance of ω-6 and ω-9 UFAs present in PSO, suggesting this oil as alternative therapy for the treatment of inflammatory skin diseases. Further investigations are needed to support its application in clinical practice.

Biblioteca responsável: BR68.1