Demonstration of amoeboid and ramified microglial cells in pre- and postnatal bovine brains by lectin histochemistry

Journal/Book: Ann. Anat. 178, 25-31. 1996;

Abstract: In embryonic, fetal and postnatal bovine brains the development anddistribution of microglial cells was examined by lectin histochemistry,using the isolectin B4 from Griffonia simplicifolia (GSA I-B4), thelectin from Ricinus communis (RCA-I), and mistletoe lectin (ML I). WithGSA I-B4 and ML I, different types of microglial cells, i.e., amoeboid,intermediate and ramified cells, were specifically stained. On sectionsfixed in Bouin's fluid significantly higher numbers of microglial cellswere labelled than on sections fixed in formalin. On the latter,proteolytic pretreatment was required. With RCA-I, no staining ofmicroglial cells was achieved. This finding may indicate the presence ofvery low concentrations of beta-D-galactose residues on bovinemicroglial cells in comparison with other species studied so far. In thefetal telencephalon, the highest numbers of amoeboid microglial cellswere found in transitory structures (subependymal regions of the lateralventricles, cavum septi pellucidi, intermediate zone) and in areas ofdeveloping axon tracts (corpus callosum, internal and external capsules)between three and five months of gestational age. From 3-4 months ofgestational age onward, the appearance of ramified microglial cells wasnoted. In 7-8 month-old fetuses, a complete change of the microglialcell picture occurred. Ramified cells clearly predominated, whereasamoeboid cells had markedly decreased. In 8-9 month-old fetuses,amoeboid microglial cells had almost disappeared from fetal brains. Inbrains from subadult and adult cattle, lectin-positive ramifiedmicroglial cells with up to five cellular processes were seen in allbrain areas, located adjacent to vessels or surrounding neuronalperikarya. Author.

Keyword(s): AGING/PH (physiology)

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