ABSTRACT
PURPOSE: To evaluate the in vivo and in vitro toxicity of sunitinib malate, a multikinase inhibitor molecule. DESIGN: Experimental, Prospective, Controlled. METHODS: Human retinal pigment epithelial (ARPE-19) and human umbilical vein endothelialcells (HUVECS) were used in a culture toxicity test and exposed to different concentrations of sunitinib malate for 18 hours. The HUVECs also were cultured to evaluate the angiogenesis inhibitory effect of sunitinib malate. Fundus photography and angiographic, electrophysiologic, and histopathologic evaluations with light and electron microscopy were performed in two groups of five rabbits each that received different intravitreal concentrations of the drug. Each rabbit received 0.1 ml of sunitinib malate in the right eye (one group with 12.5 mg/ml, the other group with 25 mg/ml); all animals received 0.1 ml of physiologic saline solution in the left eye. After sacrifice, the eyes were enucleated and fixed with modified Karnovsky solution. RESULTS: No toxicity related to sunitinib malate was observed using an in vitro model with the 12.5 and 25 mg/ml solutions in HUVEC and ARPE cell cultures. No toxicity was observed in the in vivo model with 12.5 mg/ml, but light microscopy showed that the 25 mg/ml solution damaged the photoreceptors layer. No functional changes in the electroretinogram were observed in any group. CONCLUSIONS: Sunitinib malate 12.5 mg/ml caused no toxicity in in vivo and in vitro models, but the 25 mg/ml concentration caused retinal changes suggesting toxicity in the in vivo model. Further research with the drug is needed in models of ocular neovascularization.
Subject(s)
Angiogenesis Inhibitors/toxicity , Antineoplastic Agents/toxicity , Endothelium, Vascular/drug effects , Indoles/toxicity , Photoreceptor Cells, Vertebrate/drug effects , Pyrroles/toxicity , Retinal Pigment Epithelium/drug effects , Animals , Cell Count , Cell Line , Dose-Response Relationship, Drug , Electroretinography/drug effects , Fluorescein Angiography , Humans , Intravitreal Injections , Photoreceptor Cells, Vertebrate/ultrastructure , Protein-Tyrosine Kinases/antagonists & inhibitors , Rabbits , Retinal Ganglion Cells/drug effects , Retinal Ganglion Cells/ultrastructure , Sunitinib , Umbilical Veins/cytologyABSTRACT
Systemic injection of pilocarpine in rodents induces status epilepticus (SE) and reproduces the main characteristics of temporal lobe epilepsy (TLE). Different mechanisms are activated by SE contributing to cell death and immune system activation. We used BALB/c nude mice, a mutant that is severely immunocompromised, to characterize seizure pattern, neurochemical changes, cell death and c-Fos activation secondarily to pilocarpine-induced SE. The behavioral seizures were less severe in BALB/c nude than in BALB/c wild type mice. However, nude mice presented more tonic-clonic episodes and higher mortality rate during SE. The c-Fos expression was most prominent in the caudate-putamen, CA3 (p<0.05), dentate gyrus, entorhinal cortex (p<0.001), basolateral nucleus of amygdala (p<0.01) and piriform cortex (p<0.05) of BALB/c nude mice than of BALB/c. Besides, nude mice subjected to SE presented high number of Fluorojade-B (FJB) stained cells in the piriform cortex, amygdala (p<0.05) and hilus (p<0.001) in comparison with BALB/c mice. A significant increase in the level of glutamate and GABA was found in the hippocampus and cortex of BALB/c mice presenting SE in comparison to controls. However, the level of glutamate was higher in the brains of BALB nude mice than in the brains of BALB/c wild type mice, while the levels of GABA were unchanged. These results indicate that the brains of immunodeficient nude mice are more vulnerable to the deleterious effects of pilocarpine-induced SE as they present intense activation, increased glutamate levels and more cell death.
Subject(s)
Brain/metabolism , Neurons/metabolism , Pilocarpine , Seizures/chemically induced , Status Epilepticus/chemically induced , Animals , Cell Count , Cell Death , Glutamic Acid/metabolism , Mice , Mice, Nude , Proto-Oncogene Proteins c-fos/metabolism , Seizures/metabolism , Status Epilepticus/metabolismABSTRACT
O estudo que constitui a parte inicial desta tese caracterizou, sob o ponto de vista histopatológico e imunohistoquímico, um processo neurodegenerativo crônico desencadeado pela indução de 2 períodos consecutivos de hipertermia por aquecimento externo (entre a quarta e a nona hora no primeiro dia de recuperação e entre a vigésima-primeira e a trigésima hora de recuperação) após a isquemia global de 10 minutos de duração no prosencéfalo de ratos wistar, sacrificados com 7 dias, 2 ou 6 meses. Verificou-se que o processo é acompanhado por vários sinais encontrados no cérebro humano afetado pela Doença de Alzheimer, incluindo-se as placas neuríticas e os novelos neurofibrilares, além da persistência da ativação microglial e do sistema citolítico do complemento. O aquecimento ambientar da gaiola não foi efetivo para a indução de hipertermia em animais controle, submetidos apenas ao procedimento cirúrgico, o que impede o controle do efeito da hipertermia durante testes comportamentais. Assim, deu-se início um segundo estudo, o qual incluiu outros 18 grupos de animais, desta vez obtendo-se a indução de um único período de hipertermia (39,5§C entre a segunda e a nona hora de recirculação) através de uma almofada de aquecimento e sob anestesia com halotano, para caracterizar-se o efeito funcional da hipertermia pós-isquêmica através do teste do labirinto aquático de Morris. Os grupos de animais foram destinados a 3 sobrevidas: 7 dias (6 grupos), 2 meses (6 grupos) e 6 meses (6 grupos). Os 6 grupos destinados para cada sobrevida foram assim constituídos: (a) animais normais, (b) animais submetidos apenas à cirurgia sem isquemia seguida de hipertermia sob halotano, (c) animais submetidos apenas à cirurgia sem isquemia seguida de normotermia sob halotano, (d) animais submetidos à isquemia sem tratamento posterior, (e) animais isquêmicos submetidos à anestesia com halotano sob temperatura normal, (f) animais submetidos à isquemia seguida de hipertermia sob anestesia com halotano. Os grupos destinados às sobrevidas de 2 e 6 meses foram avaliados sob o ponto de vista comportamental, respectivamente, após l e 5 meses de recuperação, através de testes de memória de referência, Os resultados de latência e trajeto, avaliados segundo a análise de variância para medidas repetidas, demonstraram que, em ambas as sobrevidas de 1 e 5 meses, os animais submetidos à hipertermia pós-isquêmica diferenciam-se larga e significativamente...
