RESUMO
Di(2-ethylhexyl) phthalate (DEHP) is a widely used plasticizer that is metabolized to mono(2-ethylhexyl) phthalate (MEHP). Inhalation is an important exposure route for both phthalates, and their effects on lungs include inflammation, alteration of postnatal maturation (alveolarization), enlarged airspaces and cell differentiation changes, suggesting that alveolar epithelial cells-2 (AEC) are targets of phthalates. This study evaluated the cell progression, epithelial and mesenchymal markers, including surfactant secretion in A549 cells (AEC) that were exposed to DEHP (1-100⯵M) or MEHP (1-50⯵M) for 24-72â¯h. The results showed an increased cell proliferation at all concentrations of each phthalate at 24 and 48â¯h. Cell migration showed a concentration-dependent increase at 24 and 48â¯h of exposure to either phthalate and enlarged structures were seen. Decreased levels of both surfactants (SP-B/SP-C) were observed after the exposure to either phthalate at 48â¯h, and of SP-C positive cells exposed to MEHP, suggesting a loss of the epithelial phenotype. While a decrease in the epithelial marker E-cadherin and an increase in the mesenchymal marker fibronectin were observed following exposure to either phthalate. Our results showed that DEHP and MEHP altered the structure and migration of A549 cells and promoted the loss of the epithelial phenotype.
Assuntos
Células Epiteliais Alveolares/efeitos dos fármacos , Desdiferenciação Celular/efeitos dos fármacos , Dietilexilftalato/análogos & derivados , Dietilexilftalato/toxicidade , Plastificantes/toxicidade , Proteína B Associada a Surfactante Pulmonar/antagonistas & inibidores , Proteína C Associada a Surfactante Pulmonar/antagonistas & inibidores , Células A549 , Células Epiteliais Alveolares/citologia , Células Epiteliais Alveolares/metabolismo , Antígenos CD , Biomarcadores/metabolismo , Caderinas/antagonistas & inibidores , Caderinas/metabolismo , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Forma Celular/efeitos dos fármacos , Tamanho Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Fibronectinas/agonistas , Fibronectinas/metabolismo , Humanos , Cinética , Proteína B Associada a Surfactante Pulmonar/metabolismo , Proteína C Associada a Surfactante Pulmonar/metabolismoRESUMO
BACKGROUND: In airway smooth muscle (ASM), Ca2+ influx in response to the Ca2+ depletion of the sarcoplasmic reticulum (SR) seems to play a role in the regulation of intracellular free Ca2+ concentrations ([Ca2+](i)). This study evaluates some possible Ca2+ entry pathways activated during SR-Ca2+ depletion induced by 10 mM caffeine. METHODS: Enzymatically dispersed bovine ASM cells were loaded with Fura-2/AM to permit measurement of [Ca2+](i) changes in single cells. RESULTS: Caffeine (10 mM) induced a transient increase in [[Ca2+](i) that depleted SR-Ca(2)+ content. After caffeine washout, a decrease in basal [Ca2+](i) (undershoot) was invariably observed, followed by a slow recovery. This phenomenon was inhibited by cyclopiazonic acid (5 microM). External Ca(2)+ removal in depolarized and nondepolarized cells induced a decrease in basal [Ca2+](i) that continued until depletion of the SR-Ca2+ content. The decrease in [Ca2+](i) induced by Ca2+-free physiological saline solution (PSS) was accelerated in caffeine-stimulated cells. Recovery from undershoot was not observed in Ca2+-free PSS. Depolarization with KCl and addition of D600 (30 microM) did not modify recovery. Similar results were obtained when the Na(+)/Ca2+ exchanger was blocked by substituting NaCl with KCl in normal PSS (Na(+)-free PSS) or by adding benzamil amiloride (25 microM). CONCLUSIONS: SR-Ca2+ content plays an important role in the Ca2+ leak induced by Ca2+-free medium, and does not depend on membrane potential. Additionally, recovery from undershoot after caffeine depends on extracellular Ca2+, and neither voltage-dependent Ca2+ channels nor the Na(+)/Ca2+ exchanger are involved.
Assuntos
Cafeína/farmacologia , Canais de Cálcio/efeitos dos fármacos , Sinalização do Cálcio/efeitos dos fármacos , Cálcio/metabolismo , Músculo Liso/efeitos dos fármacos , Retículo Sarcoplasmático/efeitos dos fármacos , Traqueia/citologia , Amilorida/análogos & derivados , Amilorida/farmacologia , Animais , Canais de Cálcio/fisiologia , Carbacol/farmacologia , Bovinos , Células Cultivadas , Galopamil/farmacologia , Indóis/farmacologia , Transporte de Íons/efeitos dos fármacos , Ionomicina/farmacologia , Ionóforos/farmacologia , Músculo Liso/citologia , Cloreto de Potássio/farmacologia , Retículo Sarcoplasmático/metabolismo , Trocador de Sódio e Cálcio/efeitos dos fármacos , Trocador de Sódio e Cálcio/fisiologiaRESUMO
We studied the effect of transections at the superior cerebellar peduncle during the evolution of amygdaloid kindling. Dentato- and interposito-thalamic pathways, including the ascending fastigial fibers, were transected in 10 rats at the contralateral side of the stimulated amygdala, and in other 8 at the ipsilateral side. A group of 18 rats was used as control. Contralateral lesion significantly slowed amygdala kindling, while ipsilateral lesion decreased kindled seizure duration. Furthermore, when kindled seizures were reached by 6 control rats, transection of the ipsilateral superior cerebellar peduncle led to reduction of subsequent seizures. These specific effects produced by transection of the superior cerebellar peduncle suggest that the cerebellum could exert a tonic effect over the participating circuitry used by the kindling process.