الفهرس 
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Abstract
Adult bone marrow mesenchymal stem cells (BM-MSCs) have been reported to be
able not only to differentiate into mesodermal cell types, but also they could be
reprogrammed to transdifferentiate into cells expressed ectodermal phenotypes. Recently,
hypothetically BMSCs could transdifferentiate into neuroectodermal cell types.
Cerebrospinal fluid (CSF) that fills and surrounds the central nervous system (CNS)
contains electrolytes, proteins, sugars, special growth factors and other signals. This
microenvironment promotes the neural stem cells (NSCs) commitment and differentiation
into neurons and glial cells, this occurs responding to any injury or physiological changes.
The present study aimed to induce BM-MSCs to transdifferentiate into neural-like
cells, either neurons or glial cells by using cerebrospinal fluid in vitro.
BM-MSCs were aspirated from rabbit femur, then isolated and cultured. The
undifferentiated cells were examined daily with Inverted Phase Contrast Microscopy; then
the cells were ready for the first passage ”the induction process” within 21-27day. The
undifferentiated cells were seeded in poly-D-lysin coverslips with a cell density 1×10
4
/cm
2
, and induced by adding autologous CSF into the supplemented culture media. After
that the differentiating cells in culture media were checked every day beginning with day1
till day 9and 14of incubation then the morphology of the differentiated cells were
investigated with Inverted Phase Contrast Microscope and Scanning Electron Microscope.
In addition, the differentiated cells were stained with H&E and examined with Light
Microscope. The differentiated cells were confirmed by revealing them with Cresyl violet,
Silver impregnation and Periodic Acid-Schiff’s reagent (PAS), and examined with Light
Microscopy. Finally they elucidated by immunocytochemical techniques to examine the
expression of CD145and Glial fibrillary acidic protein (GFAP) and investigated by
Confocal Laser Scanning Microscope.
The findings of the current study showed dramatic morphological and cytochemical
modifications in the cultured cells after 24h of adding auto-CSF to the culture media. The
cytomorphology of the cells were transformed from spindle or flatten shape into pyramidal
or cone-like structures with long processes that hypothesized being neuronal precursor-like
cell. As well as they were transformed into spherical or polygonal shaped with several
small branches, and supposed to be astrocyte precursor-like cell. Multipolar, bipolar and
few of pseudo-unipolar neuronal-like cells were shown in the current study. Moreover, the
length of the cell specially the neurite increased as seen by SEM
Different special stains were used to verify these findings which showed that:
Cresyl violet stain revealed the Nissl bodies found in pyramidal neuronal cell bodies
which stained with violet color. The cells’ soma displayed positive reaction with cresyl
violet stain ”Nissl stain” within 3days and raised more within 5, 7and 9days of incubation
in auto-CSF. Silver impregnation depicted the neuronal cell bodies’ processes with black
color, indicated that they contained neurofilaments characteristics of axons and dendrites.
This depiction was raised up as long as the cells incubated in auto-CSF, where the
undifferentiated cells were colorless, while within 9 and 14days of incubation the fibrous
neuronal network showed the strongest depiction. The results of Cresyl violet and Silver
impregnation stain proved that BM-MSCs differentiated into neuronal cells. Also, BM-MSCs were differentiated into astrocytes which verified by using Periodic Acid-Schiff ’
reagent (PAS) demonstrated glycogen granules which are frequently exist in astrocytes.
The cultivated cells within 1to 3days represented the weakest reaction while the strongest
reaction showed after 5days and 7days of incubation. Furthermore, the astrocyte-like cells
showed more intensive PAS reaction than neuronal cells.
Also, the results of immunocytochemical examinations for the undifferentiated
MSCs represented positive expression to the CD146marker, while the differentiated cells
expressed negative for the CD146marker. But the differentiated cells revealed positive
reaction for the glial fibrillic acid protein marker (GFAP) after 3days and strongly
positive within 5days of incubation indicating successful astrocytes differentiation.