perfusion fixation

Perfusion fixation is one of chemical fixation methods for scanning electron microscope (SEM) observation of tissues in animals.
In the method, a fixation solution is injected into the heart of an animal (specimen) undergoing anesthesia. It reaches the tissues through the blood vessels and then the tissues of the animal body are fixed. A paraformaldehyde solution (concentration: about 4.0%) or a glutalaldehyde solution (concentration: about 1.0 to 2.5%) is used to fix the tissues. The tissues can be uniformly fixed in a short time because the fixation solution is carried throughout the tissue through the blood vessels. Furthermore in this method, chemical fixation starts at the living state of the animal, autolysis after death is minimized. Thus, the method can maintain the animal tissues close to their living states. For more stable fixation, the subsequent immersion fixation is carried out after perfusion fixation. Perfusion fixation is performed until the animal suffers rigor mortis. In the case of a mouse, the rigor mortis occurs a few minutes or the perfusion fixation finishes in a few minutes.