Surgical Correction of Rectal Prolapse in Laboratory Mice (Mus musculus).

ABSTRACT

Rectal prolapse is a common clinical problem in laboratory mice. This condition may occur spontaneously, develop after genetic manipulations, result from infections with pathogens such as Citrobacter species, or arise secondary to experimental design such as colitis models. The current standard of care at our institution is limited to monitoring mice until tissue becomes ulcerated or necrotic; this strategy often leads to premature euthanasia of valuable animals prior to the study endpoint. Surgical correction of rectal prolapse is performed routinely and with minimal complications in larger species by using manual reduction with placement of a pursestring suture. In this report, we investigated whether the use of a pursestring suture was an effective treatment for mice with rectal prolapse. The procedure includes anesthetizing mice with isoflurane, manually reducing prolapsed tissue, and placing a pursestring suture of 4-0 polydioxanone. We have performed this procedure successfully in 12 mice. Complications included self-trauma, fecal impaction due to lack of defecation, and mutilation of the surgical site by cage mates. Singly housing mice for 7 d postoperatively, applying multimodal analgesia, and releasing the pursestring when indicated eliminated these complications. The surgical repair of rectal prolapses in mice is a minimally invasive procedure that resolves the clinical symptoms of affected animals and reduces the number of mice that are euthanized prematurely prior to the study endpoint.