Changes of Neurons and Blood Vessels of Human Substantia Nigra in Aging- Morphometric Study

Introduction: With aging, populations of dopaminergic neurons in the central nervous system show prominent pathological changes compared to other brain regions. Previous studies on substantia nigra were performed in cases of Parkinson's disease and in old age. Aim of the Study: Since Parkinson's disease is a disorder associated with age, it is important to examine how the relationship between neurons and blood vessels is associated with normal aging. Patients and Methods: Ten brainstems were sliced into three strata. Each stratum was sliced in semiserial sections and stained by Mallory method. Studied phases were neurons and blood vessels of substantia nigra. The analysis was conducted by camera 'Leica EC3' under the 40x magnification of light microscope 'Leica' DM 1000, using ImageJ software (version 1.42 e). Determined morphometric parameters of neurons and blood vessels were: volume and surface density, and absolute numbers per visual field. Statistical analysis was performed using SPSS software, version 16.0, using Student's t-test and Pearson correlation coefficient. Results: Volume and surface density, and total number of neurons per visual field of substantia nigra significantly decreased with age, while the volume and surface density and absolute number of blood vessels per visual field significantly increased (p < 0.05 ). Conclusion: Decrease in size and number of neurons occurs with aging, which is compensated by the increase of vascular network. This affects the supply of nutrients from the blood to neurons, as well as the availability of blood cells or toxic substances, but also the susceptibility to neuronal diseases.