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Figure 6: Microglial ingestion of carbon particle in (A) early embryo, (B) late embryo, (C) neonates and (D) adult. In case of both embryonic stages a few carbon
particles were attached to the cell (indicated by red arrows) whereas some particles become engulfed by the cell (indicated by yellow arrows). In neonates, a
phagocytic vacuole (indicated by blue arrow) with carbon particle is observed along with a cell which engulfs a carbon particle by extending its pseudopodia (indicated
by violet arrow). In an adult, an irregular shaped cell shows the same pattern of phagocytotic movement towards a carbon particle; the cell engulfs one particle and
also extends a projection towards another carbon particle (indicated by yellow & violet arrows respectively)
projection, is also observed. In neonates [Figure 3B], different groups show irregular shapes and variations.
microglia cells are found evenly dispersed throughout Representative figure of phase contrast of microglia
the brain matrix, along with other neuro-glial cells. Both isolated from young adult shows both amoeboid and
amoeboid and distinctly ramified microglia, with their ramified microglia with slender projections [Figure
long tactile projections, has now appeared. Furthermore, 4A]. These morphological variations are also supported
amoeboid microglia predominates in neonatal brain. In by immunostaining. In the case of an adult, CD11b+
the case of 3 months old rat brain or young adult [Figure cells show both irregular and elongated morphology
3C], the so called ramified microglia with their slender [Figure 4B], whereas isolated cells from neonates show
projections, elongated cell body, and nucleus are clearly rounded/irregular structures [Figure 4C]. Trypan blue-
visible and appear high in number. Similarly, cells of staining, separate from immuno-staining, was used to
amoeboid morphology are also observed. In the mature discriminate between viable (unstained) and non-viable
adult [Figure 3D], microglia, with their ramifications, cells (blue) not shown, was done to determine the yields
are found distinctively throughout brain, along with of isolated, viable cells (in percentage) from different age
other amoeboid forms. Here, ramified microglia groups [Table 1].
are prominent in the cortical region along with an
irregular shaped amoeboid form and the morphological Evaluation of the ultrastructural changes of microglial
differences are distinctly prominent. At the same time, it cells isolated from brain tissue
is seen that some deeply stained cells tethering with the Morphological variations of microglia become
margin of blood capillary or vasculature, while others prominent when isolated microglia from different
just seem to enter in to the tissue matrix. In brief silver-
gold staining shows that during pre and postnatal phase, groups is studied ultrastructurally. Microglial cells
isolated from neonates show rounded/irregular
amoeboid microglia are present predominantly, and a morphology, whereas those isolated from adult brain
few ramified form of microglia are detected in postnatal appear as irregular, elongated morphology with
phase. Whereas, in adult, both forms of microglia were
observed and a blood capillary distinctly enabling the variations. These morphological variations among
different age groups are also supported by further
entry of myeloid cells into brain parenchyma.
ultrastructural analysis. Cellular architectures of
Identification, characterisation and measurement of cell microglia isolated from brain tissue are determined
viability of isolated microglia by scanning electron microscopy (SEM). SEM studies
reveal the population of microglial cells in developing
Microglia isolated from rat brain are identified with early embryonic brain. Most of the isolated cells are
their CD11b positivity when immunostained with anti- irregularly round with serrated surface, typically
CD11b-FITC conjugated antibody. Isolated groups from monocyte/macrophage morphology in this stage of

44 Neuroimmunol Neuroinflammation | Volume 3 | Issue 2 | February 15, 2016