RESUMEN
Polymeric nanoparticles have emerged as carrier systems for molecules that release nitric oxide (NO), a free radical involved in plant stress responses. However, to date, nanoencapsulated NO donors have not been applied to plants under realistic field conditions. Here, we verified the effects of free and nanoencapsulated NO donor, S-nitroso-mercaptosuccinic acid (S-nitroso-MSA), on growth, physiological and biochemical parameters of neotropical tree seedlings kept under full sunlight in the nursery for acclimation. S-nitroso-MSA incorporation into chitosan nanoparticles partially protected the NO donor from thermal and photochemical degradation. The application of nanoencapsulated S-nitroso-MSA in the substrate favoured the growth of seedlings of Heliocarpus popayanensis, a shade-intolerant tree. In contrast, free S-nitroso-MSA or nanoparticles containing non-nitrosated mercaptosuccinic acid reduced photosynthesis and seedling growth. Seedlings of Cariniana estrellensis, a shade-tolerant tree, did not have their photosynthesis and growth affected by any formulations, despite the increase of foliar S-nitrosothiol levels mainly induced by S-nitroso-MSA-loaded nanoparticles. These results suggest that depending on the tree species, nanoencapsulated NO donors can be used to improve seedling acclimation in the nursery.
Asunto(s)
Aclimatación , Nanopartículas/metabolismo , Donantes de Óxido Nítrico/administración & dosificación , Donantes de Óxido Nítrico/farmacocinética , Óxido Nítrico/farmacocinética , Plantones/metabolismo , Luz Solar , Aclimatación/efectos de los fármacos , Aclimatación/fisiología , Aclimatación/efectos de la radiación , Portadores de Fármacos , Composición de Medicamentos , Liberación de Fármacos , Jardines , Nanopartículas/química , Donantes de Óxido Nítrico/farmacología , Fotosíntesis/fisiología , Hojas de la Planta/efectos de los fármacos , Hojas de la Planta/metabolismo , Hojas de la Planta/efectos de la radiación , S-Nitrosotioles/administración & dosificación , S-Nitrosotioles/química , S-Nitrosotioles/farmacocinética , S-Nitrosotioles/farmacología , Plantones/efectos de los fármacos , Plantones/crecimiento & desarrollo , Tiomalatos/administración & dosificación , Tiomalatos/farmacocinética , Tiomalatos/farmacología , Árboles/efectos de los fármacos , Árboles/metabolismo , Árboles/efectos de la radiación , Clima TropicalRESUMEN
Leishmaniasis is a neglected tropical disease that demands for new therapeutic strategies due to adverse side effects and resistance development promoted by current drugs. Nitric oxide (NO)-donors show potential to kill Leishmania spp. but their use is limited because of their instability. In this work, we synthesize, characterize, and encapsulate S-nitroso-mercaptosuccinic acid into chitosan nanoparticles (NONPs) and investigate their activity on promastigotes and intracellular amastigotes of Leishmania (Leishmania) amazonensis. Cytotoxicity on macrophages was also evaluated. We verified that NONPs reduced both forms of the parasite in a single treatment. We also noticed reduction of parasitophorous vacuoles as an evidence of inhibition of parasite growth and resolution of infection. No substantial cytotoxicity was detected on macrophages. NONPs were able to provide a sustained parasite killing for both L. (L.) amazonensis infective stages with no toxicity on macrophages, representing a promising nanoplatform for cutaneous leishmaniasis.
Asunto(s)
Quitosano/química , Leishmania/efectos de los fármacos , Nanopartículas/química , Donantes de Óxido Nítrico/farmacología , Compuestos Nitrosos/farmacología , Tiomalatos/farmacología , Animales , Quitosano/toxicidad , Cinética , Macrófagos/efectos de los fármacos , Ratones Endogámicos BALB C , Nanopartículas/toxicidad , Óxido Nítrico/química , Donantes de Óxido Nítrico/química , Donantes de Óxido Nítrico/toxicidad , Compuestos Nitrosos/química , Compuestos Nitrosos/toxicidad , Tiomalatos/química , Tiomalatos/toxicidad , TripanocidasRESUMEN
Bovine mastitis is a serious veterinary disease that causes great loss to the dairy industry worldwide. It is a major infectious disease and is difficult to manage and control. Furthermore, emerging multidrug resistant bacteria that cause mastitis have complicated such management. The free radical nitric oxide (NO) is a potent antimicrobial agent. Thus, the aims of this study were to prepare and evaluate the antibacterial activity of nitric oxide-releasing polymeric particles against Staphylococcus aureus (MBSA) and Escherichia coli (MBEC), which were isolated from bovine mastitis. Fifteen MBSA isolates and fifteen MBEC were collected from subclinical and clinical bovine mastitis. Biocompatible polymeric particles composed of alginate/chitosan or chitosan/sodium tripolyphosphate (TPP) were prepared and used to encapsulate mercaptosuccinic acid (MSA), which is a thiol-containing molecule. Nitrosation of thiol groups of MSA-containing particles formed S-nitroso-MSA particles, which are NO donors. The NO release kinetics from the S-nitroso-MSA particles showed sustained and controlled NO release over several hours. The antibacterial activity of NO-releasing particles was evaluated by incubating the particles with an MBSA multi-resistant strain, which is responsible for bovine mastitis. The minimum inhibitory concentration for S-nitroso-MSA-alginate/chitosan particles against MBSA ranged from 125 µg/mL to 250 µg/mL. The results indicate that NO-releasing polymeric particles are an interesting approach to combating bacteria resistance in bovine mastitis treatment and prevention.
Asunto(s)
Antibacterianos/farmacología , Escherichia coli/efectos de los fármacos , Mastitis Bovina/microbiología , Óxido Nítrico/química , Staphylococcus aureus/efectos de los fármacos , Tiomalatos/farmacología , Alginatos/química , Animales , Antibacterianos/química , Bovinos , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Quitosano/química , Escherichia coli/crecimiento & desarrollo , Femenino , Humanos , Pruebas de Sensibilidad Microbiana , Polifosfatos/química , Staphylococcus aureus/crecimiento & desarrollo , Tiomalatos/químicaRESUMEN
In this study, we demonstrate that human neuroblastoma SH-SY5Y cells transfected with human tyrosine hydroxylase isoform 1 (SH + TH cells) were substantially more resistant to cell death induced by hydrogen peroxide and 6-hydroxydopamine when compared to wild-type SH-SY5Y cells (SH cells). SH + TH cells exhibit increased levels of dopamine (DA) compared to SH cells. Incubation with hydrogen peroxide or 6-hydroxydopamine (10-100microM) for 24 h caused a significant reduction in cell viability and increased apoptosis in both cell types. However, these effects were significantly reduced in the SH + TH cells when compared to the SH cells. The SH + TH cells showed an improved ability to detoxify peroxide, which correlated with an increase in glutathione peroxidase and glutathione reductase activities, while catalase activity was unchanged. Our data suggest that a preconditioning-like mechanism linked to higher DA levels increased the resistance of SH + TH cells against oxidative insults, which is at least in part related to an augmentation in the activity of glutathione-related antioxidant enzymes.
Asunto(s)
Apoptosis , Dopamina/metabolismo , Neuroblastoma/enzimología , Estrés Oxidativo , Tirosina 3-Monooxigenasa/metabolismo , Apoptosis/efectos de los fármacos , Carmustina/farmacología , Catalasa/metabolismo , Línea Celular Tumoral , Supervivencia Celular , Relación Dosis-Respuesta a Droga , Inhibidores Enzimáticos/farmacología , Glutatión Peroxidasa/antagonistas & inhibidores , Glutatión Peroxidasa/metabolismo , Glutatión Reductasa/antagonistas & inhibidores , Glutatión Reductasa/metabolismo , Humanos , Peróxido de Hidrógeno/toxicidad , Neuroblastoma/genética , Neuroblastoma/patología , Estrés Oxidativo/efectos de los fármacos , Oxidopamina/toxicidad , Tiomalatos/farmacología , Transfección , Tirosina 3-Monooxigenasa/genéticaRESUMEN
In this study, we investigated the involvement of glutathione peroxidase-GPx in methylmercury (MeHg)-induced toxicity using three models: (a) in mouse brain after treatment with MeHg (40 mg/L in drinking water), (b) in mouse brain mitochondrial-enriched fractions isolated from MeHg-treated animals, and (c) in cultured human neuroblastoma SH-SY5Y cells. First, adult male Swiss mice exposed to MeHg for 21 days showed a significant decrease in GPx activity in the brain and an increase in poly(ADP-ribose) polymerase cleavage, an index of apoptosis. Second, in mitochondrial-enriched fractions isolated from MeHg-treated mice, there was a significant reduction in GPx activity and a concomitant decrease in mitochondrial activity and increases in ROS formation and lipid peroxidation. Incubation of mitochondrial-enriched fractions with mercaptosuccinic acid, a GPx inhibitor, significantly augmented the toxic effects of MeHg administered in vivo. Incubation of mitochondrial-enriched fractions with exogenous GPx completely blocked MeHg-induced mitochondrial lipid peroxidation. Third, SH-SY5Y cells treated for 24 h with MeHg showed a significant reduction in GPx activity. There was a concomitant significant decrease in cell viability and increase in apoptosis. Inhibition of GPx substantially enhanced MeHg toxicity in the SH-SY5Y cells. These results suggest that GPx is an important target for MeHg-induced neurotoxicity, presumably because this enzyme is essential for counteracting the pro-oxidative effects of MeHg both in vitro and in vivo.