Altered defaecatory behaviour and faecal incontinence in a video-tracked animal model of pudendal neuropathy.
OBJECTIVE
The aim was to develop a behavioural animal model of faecal continence and assess the effect of retro-uterine balloon inflation (RBI) injury. RBI in the rat causes pudendal neuropathy, a risk factor for obstetric related faecal incontinence in humans.


METHODS
Video-tracking of healthy rats (n = 12) in a cage containing a latrine box was used to monitor their defaecatory behaviour index (DBI) over 2 weeks. The DBI (range 0-1) was devised by dividing the defaecation rate (pellets per hour) outside the latrine by that of the whole cage. A score of 0 indicates all pellets were deposited in the latrine. Subsequently, the effects of RBI (n = 19), sham surgery (n = 4) and colostomy (n = 2) were determined by monitoring the DBI for 2 weeks preoperatively and 3 weeks postoperatively.


RESULTS
The DBI for healthy rats was 0.1 ± 0.03 with no significant change over 2 weeks (P = 0.71). In the RBI group, 13 of 19 rats (68%) showed no significant change in DBI postoperatively (0.08 ±  -0.05 vs 0.11 ±  -0.07) while in six rats the DBI increased from 0.16 ±  -0.09 to 0.46 ± 0.23. The negative control, sham surgery, did not significantly affect the DBI (0.09 ± 0.06 vs 0.08 ± 0.04, P = 0.14). The positive control, colostomy, increased the DBI from 0.26 ± 0.03 to 0.86 ± 0.08.


CONCLUSIONS
This is the first study showing a quantifiable change in defaecatory behaviour following injury in an animal model. This model of pudendal neuropathy affects continence in 32% of rats and provides a basis for research on interventions for incontinence.
School of Medicine and Medical Science, University College Dublin, Dublin, Ireland.
L A
LA
Devane
School of Medicine and Medical Science, University College Dublin, Dublin, Ireland.
E
E
Lucking
School of Medicine and Medical Science, University College Dublin, Dublin, Ireland.
J
J
Evers
School of Medicine and Medical Science, University College Dublin, Dublin, Ireland.
M
M
Buffini
National Bowel Research Centre (NBRC) and GI Physiology Unit, Queen Mary University of London, London, UK.
S M
SM
Scott
National Bowel Research Centre (NBRC) and GI Physiology Unit, Queen Mary University of London, London, UK.
C H
CH
Knowles
School of Medicine and Medical Science, University College Dublin, Dublin, Ireland.|Centre for Colorectal Disease, St Vincent's University Hospital, Dublin, Ireland.
P R
PR
O'Connell
School of Medicine and Medical Science, University College Dublin, Dublin, Ireland.
J F X
JFX
Jones
D000818:Animals; D003672:Defecation / Q000502:physiology*; D004195:Disease Models, Animal; D005242:Fecal Incontinence / Q000209:etiology / Q000503:physiopathology*; D005260:Female; D060545:Pudendal Neuralgia / Q000209:etiology / Q000503:physiopathology*; D051381:Rats; D012187:Retroperitoneal Space / Q000293:injuries; D058738:Uterine Balloon Tamponade / Q000009:adverse effects*; D014599:Uterus / Q000293:injuries*; D014741:Video Recording
Faecal incontinence; animal model