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Determining integrity of bladder innervation and smooth muscle function 1 year after lower spinal root transection in canines
Author(s) -
Salvadeo Danielle M.,
Tiwari Ekta,
Frara Nagat,
Mazzei Michael,
Brown Justin M.,
Braverman Alan S.,
Barbe Mary F.,
Ruggieri Michael R.
Publication year - 2018
Publication title -
neurourology and urodynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.918
H-Index - 90
eISSN - 1520-6777
pISSN - 0733-2467
DOI - 10.1002/nau.23765
Subject(s) - medicine , reinnervation , urinary bladder , anatomy , nerve root , detrusor muscle , h&e stain , urination , spinal nerve , urology , pathology , dorsum , urinary system , immunohistochemistry
Aims To assess bladder smooth muscle function and innervation after long‐term lower spinal root transection in canines. Methods Thirteen female mixed‐breed hound dogs underwent bladder decentralization, which included transection of all sacral dorsal and ventral roots caudal to L7 and hypogastric nerves, bilaterally ( n = 3); all sacral roots and hypogastric nerves plus transection of L7 dorsal roots, bilaterally ( n = 4); or a sham operation ( n = 6). At a year after initial surgery, bladder function was assessed in vivo by stimulation of the pelvic plexus. The bladder tissue was harvested for ex vivo smooth muscle contractility studies. Remaining bladder was evaluated for nerve morphology immunohistochemically using neuronal marker PGP9.5, apoptotic activity using terminal deoxynucleotidyl transferase dUTP nick end labeling, and histopathology using a hematoxylin and eosin stain. Results Sacral root decentralization did not reduce maximum strength of pelvic plexus stimulation‐induced bladder contraction, although long‐term sacral dorsal and ventral root plus L7 dorsal root transection significantly decreased contraction strength. Electric field stimulation‐induced contractions of the detrusor from all decentralized animals were preserved, compared to controls. Viable nerves and intramural ganglia were visualized in the bladder wall, regardless of group. There was no difference in amount of apoptosis in bladder smooth muscle between groups. Conclusion Bladder smooth muscle cells maintain their function after long‐term bladder decentralization. While pelvic plexus‐induced bladder contractions were less robust at 1 year after lower spinal root transection, the absence of atrophy and preservation of at least some nerve activity may allow for successful surgical reinnervation after long‐term injury.