Sildenafil promotes neuroprotection of the pelvic ganglia neurones after bilateral cavernosal nerve resection in the rat.
OBJECTIVE
To determine the gene expression profile of pelvic ganglia neurones after bilateral cavernosal nerve resection (BCNR) and subsequent treatment with sildenafil in relation to neurotrophic-related pathways.


METHODS
Fisher rats aged 5 months were subjected to BCNR or sham operation and treated with or without sildenafil (20 mg/kg body-weight in drinking water) for 7 days. Total RNA isolated from pelvic ganglia was subjected to reverse transcription and then to quantitative reverse transcriptase-polymerase chain reaction (PCR) with the RAT-neurotrophic array. Results were corroborated by real-time PCR and western blotting. Another set of animals were injected with a fluorescent tracer at the base of the penis, 7 days before BCNR or sham operation, and were sacrificed 7 days after surgery. Sections of pelvic ganglia were used for immunohistochemistry with antibodies against neurturin, neuronal nitric oxide synthase, tyrosine hydroxylase and glial cell line-derived neurotrophic factor receptor α2.


RESULTS
A down-regulation of the expression of neuronal nitric oxide synthase accompanied by changes in the level of cholinergic neurotrophic factors, such as neurturin and its receptor glial cell line-derived neurotrophic factor receptor α2, artemin, neurotrophin-4 and cilliary neurotrophic factor, was observed 7 days after BCNR in pelvic ganglia neurones. Treatment with sildenafil, starting immediately after surgery, reversed all these changes at a level similar to that in sham-operated animals.


CONCLUSIONS
Sildenafil treatment promotes changes in the neurotrophic phenotype, leading to a regenerative state of pelvic ganglia neurones. The present study provides a justification for the use of phosphodiesterase 5 inhibitors as a neuroprotective agent after BCNR.
Department of Internal Medicine, Charles R. Drew University of Medicine & Science, Los Angeles, CA 90059, USA.
Su M
SM
Hlaing
Leah A
LA
Garcia
Istvan
I
Kovanecz
Ramon A
RA
Martinez
Sanjana
S
Shah
Jorge N
JN
Artaza
Monica G
MG
Ferrini
D000818:Animals; D005725:Ganglia, Autonomic / Q000187:drug effects* / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors / Q000235:genetics* / Q000378:metabolism; D008297:Male; D009474:Neurons / Q000378:metabolism; D018696:Neuroprotective Agents / Q000494:pharmacology*; D051101:Neurturin / Q000378:metabolism; D052248:Nitric Oxide Synthase Type I / Q000378:metabolism; D059351:Organ Sparing Treatments / Q000379:methods; D010388:Pelvis / Q000294:innervation; D010413:Penis / Q000187:drug effects / Q000294:innervation* / Q000601:surgery; D058986:Phosphodiesterase 5 Inhibitors / Q000494:pharmacology*; D010879:Piperazines / Q000494:pharmacology*; D011687:Purines / Q000494:pharmacology; D051381:Rats; D011916:Rats, Inbred F344; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects; D000068677:Sildenafil Citrate; D013450:Sulfones / Q000494:pharmacology*
D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors; D018696:Neuroprotective Agents; D051101:Neurturin; D058986:Phosphodiesterase 5 Inhibitors; D010879:Piperazines; D011687:Purines; D013450:Sulfones; D000068677:Sildenafil Citrate; D052248:Nitric Oxide Synthase Type I