FIG. 3.

A schematic representation of the experimental procedures of a typical preclinical stem cell therapy for ED. The donor rat and recipient rat can be the same (autologous) or different (allogeneic). The isolation and cultivation of SCs vary from one type to another. Modification and sorting of SCs are desired by some researchers, although a higher benefit versus risk ratio has not been demonstrated. Labeling of SCs, which is unnecessary if from a GFP donor rat, usually incorporates a chemical agent that can be later detected by color or fluorescence. Transplantation of the labeled SCs has so far been conducted universally by IC injection, as indicated with the cross-sectional view of the penis of an animal whose erectile function has been compromised by various means, for example, CN injury and streptozotocin injection. Weeks or months after SC transplantation, the animals are tested for erectile function, usually by measurement of increases in intracavernous pressure (ICP) during electrostimulation of CN. The animals are then sacrificed for histological assessment of corpus cavernosum and identification of the injected SCs. SCs, stem cells; GFP, green fluorescence protein; IC, intracavernous; CN, cavernous nerve.