T. Papacocea 1, Raluca Papacocea 2, Anca Bădărău 2, Magda Buraga 2, Cătălina Ciornei 2, A. Papacocea 3, Irina Stoian 4
1 Clinica de Neurochirurgie, Spitalul de Urgenţă “Sf. Pantelimon”, Bucureşti
2 Departamentul de Fiziologie, UMF “Carol Davila”, Bucureşti
3 Clinica de Microneurochirurgie, Institutul de Boli Cerebrovasculare, Bucureşti
4 Catedra de Biochimie, UMF “Carol Davila”, Bucureşti
Abstract
The brain aging is a complex process with anatomical, chemical and functional impact. The structural changes are not homogenonous and are related with engenous and exogenous factors. Brain aging is influenced by the oxidative stress, acting on serie of genes; the most important are related with growth hormon, histocompatibility proteins and apolipoproiein E control. Another important role in aging belongs to mitocondrial DNA, whose injuries generated by the free radicals action, increase with age in all body cells and in neurons. The mithocondrial DNA mutations accumulation seems to be a major factor in aging process. The mutations induced by the increasing of the free oxygen radicals concentration also increase with age. The psychological stress represents an important trigger for the oxydative stress induction in brain, for the reshaping of the regulatory brain structures involved in the long term emotional behavior control and for the acceleration of the brain aging. At cellular level, free oxygen radicals modulates a variety of intracellular signals, accelerating the mithosis and leading to early cellular senescence. Due to the imbalance between prooxidant and protective, antioxidant factors, proteic, lipidic and nucleic acids injuries appear. The interference between the free oxygen radicals and sinthesis, releasing and action of certain neurotrophic factors (BDNF- brain derived neurotrophic factor, NGF-nerve growth factoe, neurotensins, FGF- fibroblast growth factor, GDNF-glial derived growth factor) is reflected by the survival changes of specific populations of neurons. The impact on oxidative stress on neurogenesis was also analyzed. Neurogenesis is still present, but reduced in aging brain. The neurogenesis stimulation by factors which control it, represents not only a theorethical possibility but receives practical valences, as is reflected by the newest studies.