[Morphometric assessment of lesions in the dopaminergic nigrostriatal system in Parkinson disease].

The qualitative changes in substantia nigra were analysed in the material of 25 cases of Parkinson's disease. A morphometric quantitative study of depletion of pigmented dopaminergic cells of substantia nigra was performed in six long-term cases of the disease. In addition, the number of melanin nodules was assessed as a marker of cell disintegration. The results obtained were compared with the morphometric evaluation of neuronal depletion in the mesocorticolimbic system (ventral tegmental area-VTA). The qualitative study indicated that melanin depletion in dopaminergic cells of substantia nigra in Parkinson's disease is diffuse and it is located mainly in the lateral alfa layer. Neuronal depletion with concomitant numerous extracellular neuromelanin nodules and granules was observed. A slight astrocytic gliosis free of macrophages accompanied cellular changes. The qualitative changes in substantia nigra are similar to those observed in VTA. The morphometric evaluation revealed that depletion of dopaminergic neurons in substantia nigra in Parkinson's disease is 73%, on average, while in VTA it remains under 5%. Hence, depletion in substantia nigra is much more intense. The analysis of the relationship between the number of neurons in substantia nigra and the age of subjects in the control group indicated that the number of neurons decreased proportionally to the age. In the group under study no significant relationship between neurons depletion and duration of disease or patients age was found. In the studied group of patients with Parkinson's disease, the number of melanin nodules in substantia nigra was significantly higher than in controls.