This week, I was able to observe Feng performing transcardial perfusion, a technique used to prepare tissue for immunohistochemistry.
The subject animal (in this case, a mouse) is deeply anesthetized before surgery is performed to expose the heart.
Gage, G. J., Kipke, D. R., Shain, W. Whole Animal Perfusion Fixation for Rodents. J Vis. Exp. (65), e3564, doi:10.3791/3564 (2012). |
A perfusion needle is placed in the left ventricle (the chamber of the heart responsible for pumping blood to the rest of the body), and a saline solution is then pumped at constant pressure through the circulatory system before exiting through an incision made to the right atrium. This clears the subject of blood.
Gage, G. J., Kipke, D. R., Shain, W. Whole Animal Perfusion Fixation for Rodents. J Vis. Exp. (65), e3564, doi:10.3791/3564 (2012). |
A paraformaldehyde (PFA) solution is then accordingly pumped through the cleared circulatory system, quickly and consistently preserving the tissue in a life-like state.
Gage, G. J., Kipke, D. R., Shain, W. Whole Animal Perfusion Fixation for Rodents. J Vis. Exp. (65), e3564, doi:10.3791/3564 (2012). |
The fixed tissue can then be harvested and stored for later experiment. For our experimental needs, whole animal perfusion fixation yields the best possible preservation of the brain for immunohistochemistry.
Gage, G. J., Kipke, D. R., Shain, W. Whole Animal Perfusion Fixation for Rodents. J Vis. Exp. (65), e3564, doi:10.3791/3564 (2012). |
Through my observation, I learned that safety and sterility, for both the animal subject and the human investigator, are of the utmost important in any procedure of this nature. Due to the toxic characteristice of PFA, all work is done under the fume hood, and gloves and a lab coat are donned at all times. And because our lab works with both live tissue and fixed tissue, we have a special set of tools put aside for each, to ensure that no cross-contamination occurs.
It was a very good learning experience, and I enjoyed helping with the set-up and clean-up for the procedure. I'm sure that as Laura begins to undertake her own immunohistochemistry experiments in the future, I'll be assisting with many more perfusions.