Veterinary session

Astroglial heterogeneity is one of the lesser investigated areas of neuroscience, especially regarding primates. We aimed to quantitatively analyse the different astroglia populations in the frontal lobe and the caudate nucleus of several primate species from the main taxonomic groups (Hominidae, Old World monkeys, New World monkeys, Lemuridae).

Immunohistochemical analysis was performed on formalin-fixed paraffin-embedded brain tissue samples. Astroglia-specific antibodies against glial fibrillary acidic protein (GFAP) and aldehyde dehydrogenase (ALDH1L1) were used. We digitalized the slides using a slide scanner, then analyzed the morphometric and topographic properties of the astroglia populations by means of manual cell annotation. Our results showed that the GFAP+ and ALDH1L1+ astroglia populate the frontal lobe and caudate nucleus mainly in a complimentary fashion. Importantly, the density of ALDH1L1+ astroglia was 1,5 times higher than the GFAP+ population in all species examined, raising further questions regarding specific astroglial subpopulations. The current study is the first part of a comprehensive investigation, which aims to reveal the evolutionary mechanisms underlying the diversification of the astroglia in humans.