Intracellular water and ionic shifts during growth and ageing of rats

Electron probe microanalysis of cytoplasmic concentrations of elements in a single cell in culture and suspension

Electron probe microanalysis is a method for evaluation of concentrations of elements at the subcellular level, effective in studies of an individual cell in culture or suspension. Intracellular concentrations of cytoplasmic ions (K+, Na+, Cl-) most rapidly and markedly reacting to changes is an adequate criterion for evaluating the traumatism of manipulations used in cell technologies. Using electron probe microanalysis it will be possible to develop special procedures (for example, therapeutic cloning) for reprogramming or cryopreservation, when intactness of intracellular balance of element serves as the criterion of cell status.

Caloric restriction, aging, and antioxidant enzymes

The basic mechanisms of aging and its retardation by caloric restriction (CR) remain unclear. One suggested means by which CR could retard aging is based on production of mitochondrial free radicals, and efficiency of their subsequent metabolism. Currently, there is little information concerning the influences of age and CR on the rates of in vivo mitochondrial free radical production. However, evidence for CR-induced modulation of free radical detoxification capacities is mounting. The direction of the influence of CR on free radical detoxification is tissue-specific. These effects are broad and appear to provide positive advantage.

Water and ion distributions in myocytes cultured under oxidative stress mimic changes found in the process of aging

Element concentrations and local water content were measured in cytoplasm, nuclei, mitochondria and lipofuscin granula (LG) of isolated cardiac myocytes of the rat. Cells were cultured for 14 days under either 5%, 20% or 40% ambient oxygen concentration. LG were found to contain less cations and more phosphorous than mitochondria, which might be related to their lower protein and higher lipid content. Under oxidative stress, dehydration of mitochondria occurred, while their cation content remained constant. This is the same pattern of changes as found in cells in situ of aging rats. Therefore, it is concluded that peroxidative damage via oxygen derived free radicals is the reason for the mitochondrial water loss in the process of aging.

Morphological changes of isolated rat liver mitochondria during Fe2+/ascorbate-induced peroxidation and the effect of thioctacid

Fe2+/ascorbate-induced peroxidation of isolated rat liver mitochondria leads to initial volume changes and, ultimately, to severe damage characterized by gross swelling and loss of cristae and matrix material. Only the last phase is associated with significant production of malondialdehyde. The shrinkage of mitochondria during the onset of peroxidation matches changes observed in mitochondria of aging animals. Thioctacid (alpha-lipoic acid) prevents this initial shrinkage. However, its main effect in the system studied here is inhibition of active respiration.