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Figure 7: Quantification of phagocytosis using a colorimetric NBT assay. ROS generation by cells from different age groups in normal conditions was measured by
using the colorimetric NBT assay done in triplicate set. Data are statistically interpreted by using one-way ANOVA followed by Tukey-Kramer test used for post-hoc
multiple comparisons where P < 0.05 is considered significant. Significant difference associated with phagocytic ability present between different age groups where
P value is less than 0.05 indicated by * symbol in graph. Graphical representation shows there is a significant increase of phagocytic ability in both late embryo and
neonates as compared to the early embryo (indicated by * mark) whereas in case of adult the variation is insignificant with early embryo. Significant difference in
phagocytic potential between these two groups (late embryo and neonates) with the adult is also indicated by * symbol
developing brain [Figure 5A]. This pattern [Figure engulfing carbon particle in one cell and pseudopodial
5B] is gradually changing where the amoeboid extension phagocytising carbon particle by another is
cells appear with extended pseudopodia or cellular visible [Figure 6C]. In case of adult, cell shows engulfed
projections in the late embryonic phase. Figure 5C carbon particles along with a pseudopodial projection
reveals the presence of both amoeboid microglia that entangle another carbon particle to draw and engulf
and the extended structure of a microglial cell. [Figure 6D]. Measurement of phagocytosis in terms of
Both of them are showing active phagocytic forms. oxidative burst is done in different age groups without
When an animal develops from infant to adulthood any external stimulus and the animals maintained
its microglial structure changes from rounded to in normal condition. So the values of phagocytosis of
elongated ramified forms. In an adult [Figure 5D], a different age groups reflect their baseline phagocytic
cell shows an elongated structure with projection and capacity in normal condition. The OD value is directly
a few slender filopodia that are prominent at the edge proportional to their phagocytic capacity. This shows a
of the cell. This is the ramified, or so called resting, prominent age dependent trend of phagocytic capacity.
form that is characteristic of microglial populations In early embryonic stage when they enter and populate
observed in adult brains. in huge number to the brain parenchyma, they show
less phagocytic potential. But it shows high phagocytic
Phagocytosis by microglia isolated from different age capacity at the late embryonic stage and continues for
groups of animals few days just after birth. Afterwards, during resting
stage in stable adult brain this activity reaches to a basal
Carbon particle ingestion shows the phagocytic activity level which is comparable to the early embryonic stage
in all stages from early embryo to adult. Carbon particle [Figure 7]. Statistical interpretation of the data by one
ingested or adhere to the cell is found in both embryos way ANOVA, followed by Tukey-Kramer test used for
[Figure 6A and B]. In neonates, phagocytic vacuole post-hoc multiple comparisons, shows that there is a

Neuroimmunol Neuroinflammation | Volume 3 | Issue 2 | February 15, 2016 45