Interactions between Microglia and Oligodendrocytes in the Caudate Nucleus in Attack-like Progressive Schizophrenia

Background : previously, the authors found ultrastructural pathology of oligodendrocytes in contact with microglia in the white matter of the prefrontal cortex in attack-like progressive schizophrenia. Aim of the study : to determine ultrastructural changes in microglia and oligodendrocytes in contact with each other and to analyze correlations between ultrastructural components of microglia and oligodendrocytes in the caudate nucleus of attack-like-progressive schizophrenia compared to controls. Material and Methods : an electron microscopic morphometric study of microglia and oligodendrocytes in contact with each other was performed in autopsy head of the caudate nucleus from the left hemisphere in 10 cases of attack-like progressive schizophrenia and 20 controls without mental pathology. Group comparisons were made using ANCOVA and Pearson correlation analysis. Results : we found decreased volume fraction (Vv) and the number of mitochondria in microglia and oligodendrocytes, decreased area of microglia and increased Vv of heterochromatin and area of vacuoles of endoplasmic reticulum in oligodendrocytes in schizophrenia compared to controls. The area of microglia correlates positively with the areas of oligodendrocyte cytoplasm and mitochondria in oligodendrocytes in the schizophrenia group but not in the control group. The areas of oligodendrocytes, microglia and of their nuclei correlate positively with age at onset of disease. Vv and number of mitochondria in microglia correlate positively with the same parameters in oligodendrocytes in the control group, but not in the schizophrenia group. Vv and number of mitochondria in microglia correlate negatively with the perimeter of heterochromatin in oligodendrocytes in the schizophrenia group. Conclusion : The obtained results showed reduced microglial reactivity in the caudate nucleus in attack-like progressive schizophrenia. Dystrophy of oligodendrocytes in schizophrenia is associated with a decrease in the size of microglia, a deficiency of mitochondria in microglia and oligodendrocytes, and disrupted bioenergetics coupling between microglia and oligodendrocytes. Dystrophic changes in microglia and oligodendrocytes in the caudate nucleus in attack-like progressive schizophrenia may be associated with dysontogenesis.