Sprague-Dawley rats, postnatal day 120 (P120), were obtained from Charles River. Animals were cared for in accordance with the National Research Council publication Guide for Care and Use of Laboratory Animals.
Cavernous Nerve Injury
P120 Sprague-Dawley rats were randomized into two groups: bilateral CN resection (n = 46) and sham abdominal exploration (control, n = 46).
Five-millimeter sections of the cavernous nerve were removed bilaterally using a KAPS industrial microscope under direct vision through a midline abdominal incision. The prostatic capsule was manipulated in control animals without resecting the cavernous nerve. Stress-related fluctuations of serum testosterone were minimized at the time of abdominal exploration through bilateral epididymo-orchiectomy and subcutaneous placement of a 2-cm piece of medical grade Silastic tubing (Dow Corning Corp., Midland, MI) filled with crystalline testosterone. This method ensures reliable, uniform serum testosterone levels for both the control and intervention groups up to 28 days after placement. Penes were harvested from euthanized males by sharp dissection 2, 4, 7, 14, and 21 days after CN resection and were either frozen in liquid nitrogen or fixed in 4% paraformaldehyde.