RESUMO
The effect of separate and combined 10-day treatment with phenobarbital (PB) in a single daily dose of 35 mg/kg and E. coli lipopolysaccharide (LPS) in a dose of 25 microg/kg was studied in white rats. The results were evaluated by the rate of DNA synthesis in the culture of T mitogen stimulated thymocytes, the activity of glucose-6-phosphate dehydrogenase (G-6-PDG) in the thymus, and the activity of acetylcholine esterase (ACE) and the content of catecholamines (CA) in the nerve fibers of this organ. It was established that the 10-day treatment with PB inhibits the proliferative activity in concanavalin A stimulated lymphocytes of rat thymus, decreases the ACE activity, and increases the CA content in the nerve fibers. The repeated injections of E. coli LPS on the background of PB led to more pronounced negative changes in the functional activity of lymphoid cells in the thymus, manifested by a decrease in the G-6-PDG activity and the rate of DNA synthesis in the thymus and by an increase in the level of biogenic amines in the nervous fibers of this organ.
Assuntos
Anticonvulsivantes/farmacologia , Hipnóticos e Sedativos/farmacologia , Lipopolissacarídeos/farmacologia , Fenobarbital/farmacologia , Timo/efeitos dos fármacos , Acetilcolinesterase/metabolismo , Animais , Catecolaminas/metabolismo , Divisão Celular/efeitos dos fármacos , Concanavalina A/farmacologia , Interações Medicamentosas , Escherichia coli , Glucosefosfato Desidrogenase/metabolismo , Masculino , Fibras Nervosas/metabolismo , Ratos , Timo/citologia , Timo/inervaçãoRESUMO
Effects of two types of low-intensity electromagnetic fields (EMF) of industrial frequency (50 Hz) on the fine structure and proliferative activity of thymic cells in white rats were studied. It was found that a weak EMF with a prevailing electrical component (380-480 V/m, 120-140 nT1) did not affect the DNA synthesis intensity. An EMF with a stronger magnetic induction (10-15 V/m, 800-1500 nT1) diminished the glucose-6-phosphate dehydrogenase activity and proliferative processes in cultured stimulated lymphocytes. Electron microscopic investigation of the thymus after both types of exposure revealed an accumulation of lymphocytes with pyknotic nuclei and electron-dense cytoplasm, as well as hypoplasia of the vascular endothelium. At the same time, EMF with a prevailing magnetic component produced a more marked negative effect on the ultrastructure of thymic cells, which indicated a lowered secretory activity of epitheliocytes.
Assuntos
Timo/efeitos da radiação , Timo/ultraestrutura , Animais , Divisão Celular/efeitos da radiação , Relação Dose-Resposta à Radiação , Campos Eletromagnéticos , Masculino , Exposição Ocupacional , Ratos , Ratos WistarRESUMO
Hormonal status (blood content of triiodothyronine, thyroxin, insulin, 11-hydroxycorticosteroids), dehydration in the Krebs cycle, and activity of the first enzyme in the pentose-phosphate cycle, glucose-6-phosphate dehydrogenase, in the brain and myocardium of white rats were studied at different time periods after separate and combined prolonged exposure to radiation in relatively small doses and heat. It was found that combination of ionizing radiation and heat led to hypofunction of the endocrine glands and inhibition of dehydration processes in the Krebs Cycle.