RESUMO
We investigated the oxygen (O(2)) uptake of equine articular chondrocytes to assess their reactions to anoxia/re-oxygenation. They were cultured under 5% or 21% gas phase O(2) and at glucose concentrations of 0, 1.0 or 4.5g/L in the culture medium (n=3). Afterwards, the O(2) consumption rate of the chondrocytes was monitored (oxymetry) before and after an anoxia period of 25min. The glucose consumption and lactate release were measured at the end of the re-oxygenation period. The chondrocytes showed a minimal O(2) consumption rate, which was hardly changed by anoxia. Independently from the O(2) tension, glucose uptake by the cells was about 30% of the available culture medium glucose, thus higher for cells at 4.5g/L glucose (n=3). Lactate release was also independent from O(2) tension, but lower for cells at 4.5g/L glucose (n=3). Our observations indicated that O(2) consumption by equine chondrocytes was very low despite a functional mitochondrial respiratory chain, and nearly insensitive to anoxia/re-oxygenation. But the chondrocytes metabolism was modified by an excess of O(2) and glucose.
Assuntos
Cartilagem Articular/citologia , Cartilagem Articular/efeitos dos fármacos , Condrócitos/efeitos dos fármacos , Condrócitos/metabolismo , Glucose/farmacologia , Consumo de Oxigênio/efeitos dos fármacos , Oxigênio/farmacologia , Alginatos/metabolismo , Animais , Contagem de Células , Técnicas de Cultura de Células , Separação Celular , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Ácido Glucurônico/metabolismo , Ácidos Hexurônicos/metabolismo , Cavalos , Ácido Láctico/biossíntese , MicroesferasRESUMO
The evolution of mitochondrial oxidative phosphorylation was studied during cancer induction in a model of thymic radiolymphomagenesis in C57BL/Ka mice. During the preneoplastic period, thymuses displayed an increase of the cytochrome c oxidase activity and oxygen consumption together with oxidative DNA damage assessed by the presence of the 8-hydroxydeoxyguanine DNA base modification. These transient changes in mitochondrial functional activity were not observed in thymuses of mice rescued from lymphoma development by a bone marrow graft, suggesting an important role of mitochondria for neoplastic transformation in this model, which might therefore be of interest to test the utilization of antioxidants for the prevention of radiation-induced malignancies.
