RESUMO
Follicular atresia in granulosa and theca cells occurs by apoptosis through weak hormonal stimulation. We have previously proposed an in vitro model to study this process by inducing apoptosis in BGC-1, a bovine granulosa cell line, and in primary cultures from ovaries with or without corpus luteum (CPGB+ and CPGB-, respectively), with different doses of gonadotropin releasing hormone (GnRH) analogs (leuprolide acetate (LA) as agonist and antide as antagonist). BGC-1 represent immature granulosa cells, whereas CPGB represent different degrees of luteinization. Our aim was to evaluate the intracellular pathways involved in the GnRH regulation of apoptosis in BGC-1. Treatment with LA 100nM but not with antide led to an increase in BAX over BCL-2 expression, showing antagonism of antide. All treatments inhibited phospholipase-D (PLD) activity compared to control, implying agonist behavior of antide. Progesterone in vitro production and 3ß-hydroxysteroid dehydrogenase (3ß-HSD) expression revealed different degrees of luteinization: BGC-1 were immature, whereas CPGB+ were less differentiated than CPGB-. We concluded that LA-induced apoptosis in BGC-1 occurs by activation of the mitochondrial pathway and by inhibition of PLD activity and that antide might work both as an antagonist of the intrinsic pathway and as an agonist of the extrinsic protection pathway by inhibiting PLD activity.
Assuntos
Apoptose/fisiologia , Diferenciação Celular/fisiologia , Hormônio Liberador de Gonadotropina/metabolismo , Células da Granulosa/citologia , Animais , Apoptose/efeitos dos fármacos , Bovinos , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular , Células Cultivadas , Ativação Enzimática/efeitos dos fármacos , Feminino , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Genes bcl-2/genética , Hormônio Liberador de Gonadotropina/análogos & derivados , Células da Granulosa/efeitos dos fármacos , Leuprolida/farmacologia , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Oligopeptídeos/farmacologia , Ovário/citologia , Ovário/metabolismo , Fosfolipase D/metabolismo , Transdução de Sinais , Proteína X Associada a bcl-2/genéticaRESUMO
The production of compost is one of the alternatives for the disposal of non-hazardous solid wastes. Compost is used in agriculture and gardening as fertilizer. In the State of Queretaro, Mexico, there is a project to produce compost from the municipal garbage which could be used as a fertilizer. The presence of mutagenic compounds in the compost could be a major disadvantage for the selection of this alternative. For the above reason, this study was initiated as a pilot project to determine the potential mutagenic activity in the compost using three plant bioassays: Tradescantia-micronucleus (Trad-MCN), Tradescantia stamen hair mutations (Trad-SHM) and Allium root anaphase aberrations (AL-RAA). Compost was produced using both aerobic and anaerobic processes from either organic waste (from the residential area) or from the total components of the municipal garbage. Extractions from the compost were done using distilled water and organic solvents and shaking the sample for about 12 h under relatively low temperatures (15-20 degrees C). Plant cuttings of Tradescantia or the roots of Allium were treated by submerging them in the extracts. Three replicates of each sample were analyzed in each one of the three bioassays. As expected the samples of compost from the total garbage showed a higher genetoxicity than those from organic waste. In conclusion, there are some substances present in the compost capable of inducing genotoxicity in the plant assays and therefore there must be some restrictions for its use as a fertilizer.
Assuntos
Resíduos de Alimentos , Testes de Mutagenicidade/métodos , Mutagênicos/toxicidade , Plantas/genética , Eliminação de Resíduos , Agricultura , Allium/efeitos dos fármacos , Allium/genética , Anaerobiose , Anáfase , Bioensaio/métodos , Monitoramento Ambiental/métodos , Poluentes Ambientais/toxicidade , Geografia , México , Testes para Micronúcleos , Raízes de Plantas , Plantas/efeitos dos fármacos , Saúde da População UrbanaRESUMO
We have proposed that neuronal overactivation by either stimulation of excitatory receptors or hypofunction of inhibitory circuits is a cause of excessive acetylcholinesterase (AChE) release, which, in turn, can contribute to ALS/MND pathogenesis. We investigated histochemical and histopathological changes in cell populations of the mouse spinal ventral horn upon in vivo stimulation of glutamate receptors with L-aspartate (ASP, 10-50 mg/kg, intraperitoneal: i.p.), or blockade of glycine receptors with strychnine (STRY, 2 mg/kg, i.p.). ASP in P4-P13 (postnatal age in days) but not in older mice, and STRY irrespective of age, provoked rapid, striking depletions of motor neurone AChE, and appearance of AChE activity in astrocytes. This was followed by recovery of the enzyme in most motor neurones, astrocyte activation and statistically significant changes in: brain macrophage infiltration, loss of interneurones and motor neurones and neuronophagic images including rosettes of glial cells surrounding a central 'ghost-like' motor neurone. Although AChE release preceded the neuropathology found, it is not known if its uptake is a cause of glial activation. However, it has been shown that the enzyme potentiates non-N-metyl-D-aspartate receptors identical to those that mediate astrocyte activation. AChE activity produces protons and choline, possible microglial activators. These are putative routes towards long-lasting neuropathology.
Assuntos
Acetilcolinesterase/metabolismo , Ácido Aspártico/farmacologia , Neurônios Motores/enzimologia , Estricnina/farmacologia , Fatores Etários , Animais , Contagem de Células/efeitos dos fármacos , Histocitoquímica , Interneurônios/efeitos dos fármacos , Masculino , Camundongos , Neurônios Motores/efeitos dos fármacos , Neurônios Motores/patologia , Neuroglia/efeitos dos fármacos , Neuroglia/patologia , Receptores de Glicina/antagonistas & inibidores , Medula Espinal/efeitos dos fármacos , Medula Espinal/patologia , Fatores de TempoRESUMO
To investigate the spinal cellular structures and molecular mechanisms involved in acetylcholinesterase (AChE) release evoked by both glycine (GLY) and glutamate (GLU)--responses that might play a role in chronic neurotoxicity--we analysed AChE histochemistry and histology upon systemic administration of aspartate (ASP), and conducted in vitro experiments in synaptosomes and slices prepared from mouse spinal ventral horns. Upon superfusion and incubation exposure of these preparations to GLY- and GLU-receptor agonists, we assayed both tissue content and release of AChE, butyrylcholinesterase and lactic dehydrogenase. Histochemical reduction of motor neurone (MN) AChE, calcium dependency, decreases in intracellular AChE and the ratio amongst molecular forms released, suggest that both synaptosomal GLY-evoked AChE release (GLY-EAR) and GLU-receptor-elicited AChE release (GEAR) have release sites located at MN presynaptic terminals. These responses exhibited remarkable postnatal regulation. GEAR seems to be mediated through alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid/kainate receptors after the fourth postnatal week and through both NMDA and non-NMDA receptors at earlier stages. Sustained rises of extracellular AChE might link acute excitotoxic injury with several long-lasting pathways leading to chronic neurotoxicity, since AChE molecular properties include: (1) the ability to block cholinergic mechanisms that protect MN against overactivity; (2) activation of ATP-dependent potassium channels; (3) promotion of neurite and axon outgrowth; and possibly (4) stimulation of brain macrophage migration and activation.