The dual role of microglia in the pathogenesis of multiple sclerosis

Arsakhanova Gayna Abdulaevna

Microglial cells of the Central nervous system (CNS) belong to the innate resident immune system of the brain, responsible for the physiological functioning of neurons, local immune response to injury or infection and play an important role in both healthy and pathologically altered brain and spinal cord. Microglia account for up to 10 % of the total number of glial cells in the brain. Microglia is a unique type of CNS cell that has broad functional activity. It is a kind of hybrid between white blood cells, which perform immune functions, and glial cells, whose role is to protect and support neurons in the CNS. The immunological competence of microglia differs from that of peripheral leukocytes in that microglial immune functions are controlled by inhibitory factors of neurons. Rio Hortega discovered and described microglia as a unique type of cell in the CNS with elongated processes from both poles of the cell. Under the conditions of homeostasis, the CNS microglia controls microenvironments and detects abnormalities in the work of neurons and other nerve cells, signs of traumatic or infectious damage to the brain parenchyma. This phenotype of microglia is called "resting", inactive, has branched mobile processes, although the cell body itself is in a fixed state. The presence of such a structure allows the microglia to constantly and quickly reorganize the processes for effective scanning of the microenvironment, while the cell body remains stationary so as not to disturb the local neural circuits. The role of microglia as an "observer" and its reaction to pathological situations is its most characteristic function. After activation, the microglia undergoes significant morphological changes, the processes decrease and disappear, and the cells themselves acquire an amoebic shape. There are also radical changes in gene activation and synthesis of regulatory molecules and receptors. These changes are extremely heterogeneous, since activated microglia can acquire different phenotypic traits.

Keywords:microglia, sclerosis, neurogenic diseases, neuralgia.