Visualization of the neurovascular bundles and major pelvic ganglion with fluorescent tracers after penile injection in the rat.
OBJECTIVE
To evaluate whether fluorescent tracers can consistently label the neurovascular bundles (NVBs) and major pelvic ganglion (MPG) after an intracavernosal penile injection, as the reported incidence of erectile dysfunction (ED) in men after radical prostatectomy (RP) is 55-65% and thus preservation of erectile function, sparing one or both of the NVBs remains one of the most vital factors.


METHODS
Male Sprague-Dawley rats (3 months old) received penile injections (20 microL; seven rats/group) of either deionized water (DW), Fluoro-Gold (FG), Fast-Blue (FB), Fluoro-Ruby (FR) or green fluorescent pseudorabies virus (GF-PRv). The rats were killed at 2, 3 and 14 days after injection and the NVBs and MPG were harvested and placed directly under fluorescence light. Image analysis was done by computer, coupled to a microscope equipped with a digital camera. Each NVB and MPG were analysed for its staining pattern and consistency.


RESULTS
When compared with the FB, FR and GF-PRv rats, the FG-injected rats had better staining of the NVB at 2, 3 and 14 days after injection. Under x200, FG highlighted the axons of the cavernous nerve (CN) and cell bodies (MPG). This indicates that FG injection into the penis induced the strongest CN labelling (positive staining) at 2 and 3 days after injection as compared with FB-, FR- and GF-PRv-injected rats.


CONCLUSIONS
FG injection into the penis has consistent retrograde staining of the NVBs and MPG after 3 days. Therefore, we predict that FG could potentially be used to improve the identification of the NVB in other models. However, further studies need to be carried out before these tracers can be used in humans.
Davila
Hugo H
HH
Department of Interdisciplinary Oncology at Moffitt Cancer Center, Division of Urology, University of South Florida, College of Medicine, Tampa, FL 33612, USA.
Mamcarz
Maggie
M
Nadelhaft
Irving
I
Salup
Raoul
R
Lockhart
Jorge
J
Carrion
Rafael E
RE
D000344:Afferent Pathways / Q000502:physiology; D000818:Animals; D004525:Efferent Pathways / Q000502:physiology; D007172:Erectile Dysfunction / Q000517:prevention & control; D007267:Injections; D008297:Male; D008856:Microscopy, Fluorescence / Q000592:standards*; D010410:Penile Erection / Q000502:physiology*; D010413:Penis / Q000294:innervation* / Q000503:physiopathology; D011468:Prostatectomy / Q000009:adverse effects; D051381:Rats; D017207:Rats, Sprague-Dawley