- Abstract
- Introduction
- Materials
- Methods
- Detailed Methods
- Results
- Calculations
- Discussion and Relevance
- Conclusion
- References
- Acknowledgements
- Project Info
As humans age, there is an increased propensity to develop age-related deficits in motor and cognitive performance (Carney et al., 1994; Kluger et al., 1997; Galli et al., 2002). The brain requires significant component of the body's oxygen supply and several lines of evidence now indicate that its endogenous capacity to deal with oxidative stress decreases with aging resulting in neuronal damage and functional deficits (Olanow, 1992; Caney et al., 1994; Perrig et al., 1997;). In animal and cell models, changes in neuronal lipid membranes, metabolic pathways, cellular Ca2+ homeostasis and neuronal signal transduction all appear to be affected by age and oxidative stress (Choi and Yu, 1995; Roth et al., 1995;. Denisova et al., 1997; Joseph et al., 2000).
Evidence suggests that a diet richly supplemented with fruits and vegetables may be useful in combating the long-term neuronal and behavioral decrements in function that are associated with aging and some neurodegenerative diseases (Baruts et al., 1900; Joseph et al., 1998, 1999; Galli et al., 2002). Fruits that are most effective at combating age-related deficits are those that have the highest antioxidant capacity. These include fruits such as blueberries and strawberries, that are rich in anthocyanins and other polyphenolic phytonutrients (Wang et al., 1996).
Studies using aged animals whose diet was augmented with fruits extracts such as blueberries and strawberries demonstrated that the fruit extract-supplemented animals experienced a decrease in age-related neuronal signal transduction and cognitive behavioral defects. In some cases, fruit extract supplementation completely reversed deficits in brain function, motor performance and memory in aged animals (Joseph et al., 1998, 1999). Since these fruits contain multiple polyphenolic compounds, in addition to activity, they may also have additional antinflammatory or anti-proliferative effects that could also contribute to neuroprotection.
A very important part of the cell, the Mitochondria organelle is often referred to as the powerhouse organelle, in the general animal cell. Structure wise, the mitochondria has folds inside it called cristae which are contained inside the double-layered smooth outer membrane. The inner membrane controls chemical reactions which create energy for the cell. Along rows of complex electron transport chains, which reside in the mitochondria's cristae, energy is provided for the generation of ATP. ATP is derived from metabolic oxidation as a result of complex chemical reactions
Apoptosis is a controlled cell death that keeps the intracellular content of the dying cell sequestered. A series of cellular changes: cell shrinking, loss of contact with neighboring cells, and intracellular proteins will display on the surface. The DNA is split into 180-base pairs, and the chromatin in the nucleus condenses, leading to characteristic DNA laddering. Finally, the plasma membrane begins to bloat, until it splits, leaving a residue of intracellular organelles and nucleic material. This process is also called natural cell death, as it is the natural process of a dying cell. The small particles left behind are quickly engulfed by neighboring cells and phagocytes, or, if they are not engulfed by other cells in time, the cellular particles will lyse, a process called secondary necrosis.
When a cell undergoes an unnatural death (or rather, an uncontrolled death), it is called Necrosis. The cell swells, and the mitochondra will be rendered useless, and die. The mitochondria is quite important for these tests, as it is the organelle which secretes the black discoloration when in contact with the Hoechst stain. What is worse, the cell, after neuronal necrosis, will release neurotransmitters which cause excitotoxic injury to neighboring cells. Because the mitochondria die, the cell will experience rapid loss of energy. This energy is required for apoptosis.
Neural cells have a cell body, containing a nucleus, organelles (including mitochondria), and extensions called fibers. There are different types of Neural cells, such as sensory neurons, which lead away from receptor cells, where stimulus is received, and motor neurons, which lead toward effector cells. Neural cells bunch together, creating brain tissue. Increased apoptosis in motor cells is the cause of loss of motor and cognitive function.
Copyright 2004 Gabriel Rigg, Michael
Armson, David Dickinson.
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