Neurohistology for Stem Cell Detection
- Stem cells are introduced into a living host, often to achieve changes in the host’s composition. E.g. to replace missing/lost cells; replace cells with absent or faulty protein production.
- The success of stem cell introduction is measured by a number of possible means but the initial goal is that the stem cells were placed in the correct location; that they survive and produce the changes intended. This assessment is accomplished by histologic examination of the hosts after different lapses in time after stem cell introduction.
- Optimal fixation of the host brains by transcardial perfusion optimizes the conditions to ensure successful identification of the stem cells in the host animal.
Identification of Juvenile Neurons: Double Cortin IHC Reveals Neurons That Are <7 Days Old
Stem Cell Location
A fundamental measure of efficacy for stem cell treatments is to determine whether the stem cells reached the desired location in the central nervous system. Various immunohistochemistry probes can be used to detect signature markers of the stem cells (such as a unique human protein). Also stem cells can be deliberately made to produce markers such as β-Galactosidase, green fluorescent protein or others so that subsequent staining is able to highlight the location of introduced stem cells.
Cells were tagged with β-Galactosidase, revealed by X-Gal STEM 121 (human stem cells) in mouse spinal cord
histochemistry, demonstrates a successful localization of
the newly placed cells.
Cells were tagged with β-Galactosidase, revealed by X-Gal
STEM 121 (human stem cells) in mouse spinal cord
Stem Cell Activity Example: Bromodeoxyuridine (BrdU) IHC
For some stem cell therapies, it is desirable for the cells to undergo a limited degree of division within the target organ. BrdU injection into the host animal (ip) before sacrifice (e.g. 6-12h) will allow the BrdU to be incorporated into newly formed DNA of dividing cells. BrdU masquerades for thmydine, which is only used in DNA synthesis. New cells created after the BrdU injection will contain BrdU which is detected and quantified with an antibody against BrdU.
The darkly stained cells (dots), mostly along the inner edge of
the “arrowhead” of the dentate formation indicate DNA
synthesis activity. In this manner, cell division can be witnessed
and quantified. The purple staining is normal cell body
background stained for anatomical reference.