A Comparison of Microglia Detection in Mammals and Humans Using Purinergic Receptor P2Y12 Labeling

The problem of choosing an adequate method to detect microglia is relevant for modern neurophysiological and interdisciplinary research due to the lack of universal approaches allowing visualization of this cell population in the brain of humans and laboratory animals. In the present study, the possibility of using the purinergic P2Y12 receptor as a marker for the comparative analysis of microglia in humans and some unrelated animal species (rabbit, rat, mouse, ground squirrel) was investigated. For the study, antibodies to a recombinant peptide corresponding to 303–342 amino acids of the human P2Y12 receptor were used. The best results for microglia detection were obtained in humans, rabbit, and rat. A nonspecific reaction of cells other than microglia was found in a ground squirrel and mouse, the negative impact of which on the quality of resulting images can be reduced by the means of confocal microscopy. In all cases, the absence of immunopositive macrophages and amoeboid microglial cells was observed, indicating the promising use of P2Y12 as a highly selective marker of resting microglia. The present study provides the first visualization of microglia in the brain of a rabbit and ground squirrel using antibodies to the P2Y12 receptor.