RESUMO
Phytanic acid (Phyt) accumulates in various peroxisomal diseases including Refsum disease (RD) and Zellweger syndrome (ZS). Since the pathogenesis of the neurological symptoms and especially the cerebellar abnormalities in these disorders are poorly known, we investigated the effects of in vivo intracerebral administration of Phyt on a large spectrum of redox homeostasis parameters in the cerebellum of young rats. Malondialdehyde (MDA) levels, sulfhydryl oxidation, carbonyl content, nitrite and nitrate concentrations, 2',7'-dichlorofluorescein (DCFH) oxidation, total (tGS) and reduced glutathione (GSH) levels and the activities of important antioxidant enzymes were determined at different periods after Phyt administration. Immunohistochemical analysis was also carried out in the cerebellum. Phyt significantly increased MDA and nitric oxide (NO) production and decreased GSH levels, without altering tGS, DCFH oxidation, sulfhydryl oxidation, carbonyl content and the activities of glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR) and glucose-6-phosphate dehydrogenase (G6PD). Furthermore, immunohistochemical analysis revealed that Phyt caused astrogliosis and protein nitrosative damage in the cerebellum. It was also observed that the NO synthase inhibitor Nω-Nitro-L-arginine methyl ester (L-NAME) prevented the increase of MDA and NO production as well as the decrease of GSH and the immunohistochemical alterations caused by Phyt, strongly suggesting that reactive nitrogen species (RNS) were involved in these effects. The present data provide in vivo solid evidence that Phyt disrupts redox homeostasis and causes astrogliosis in rat cerebellum probably mediated by RNS production. It is therefore presumed that disequilibrium of redox status may contribute at least in part to the cerebellum alterations characteristic of patients affected by RD and other disorders with Phyt accumulation.
Assuntos
Astrócitos/metabolismo , Cerebelo/metabolismo , Estresse Oxidativo/fisiologia , Transtornos Peroxissômicos/fisiopatologia , Ácido Fitânico/metabolismo , Espécies Reativas de Nitrogênio/metabolismo , Animais , Astrócitos/patologia , Cerebelo/crescimento & desenvolvimento , Cerebelo/patologia , Modelos Animais de Doenças , Gliose/patologia , Gliose/fisiopatologia , Homeostase/fisiologia , Masculino , NG-Nitroarginina Metil Éster/farmacologia , Fármacos Neuroprotetores/farmacologia , Transtornos Peroxissômicos/patologia , Ácido Fitânico/administração & dosagem , Ratos Wistar , Fatores de TempoRESUMO
The measurement of tongue strength contributes to the study of oro-facial physiology. The objective of this study was to investigate the influence of gender on tongue strength in young adults and to determine the differences in this strength between tongue regions. This study was conducted on 50 healthy volunteers (17 men and 33 women) with a mean age of 23 years, with no oro-facial myofunctional alterations. The strength of the anterior portion and of the dorsum of the tongue was analysed with a calibrated electronic dynamometer. The subjects were asked to apply maximum force. Men showed higher tongue strength values than women both in the anterior portion and in the dorsum of the tongue (P<0·05), and the strength of the anterior portion of the tongue was lower than that of the dorsum in both genders (P<0·05). We conclude that gender and region influenced tongue strength.