Changes in number of neurons, astrocytes and microglia in brain after ischemic stroke assessed by immunohistochemistry and immunoblotting

It is known that the mechanisms of brain damage after a stroke are regulated by interaction within several cell types, primarily neurons, astrocytes, the endothelium, and microglia. Ischemic exposure disrupts the balance in the brain cellular content; thus, in the lesion, cells die by necrosis, while delayed induction of apoptosis occurs in the tissue surrounding the ischemic zone. Named cells die in the lesion and their ratio determines the clinical outcome of the disease. Thus, the detection of deaths within various cell types of the neurovascular unit is an important part of fundamental studies of the mechanisms of brain damage and preclinical studies of potential neuroprotective drugs. For this reason, we conducted a comparative study of the two most often used methods: immunohistochemical staining of brain sections, which allows to determine the number and localization of specific cells in the tissue among other types of cells, and immunoblotting, which detects specific proteins in the tissue homogenate. We found that, depending on the cell type, changes in their number and composition after a stroke can be localized in a limited part of the tissue or cover the entire hemisphere, which imposes restrictions on the use of any method of determining the number of cells in brain tissue. In general, the most preferable is the use of immunohistochemistry; however, with certain limitations, immunoblotting can be used to determine the proportion of astroglia and microglia.