Evaluation of Cage Mate-induced Postsurgical Trauma in Mice

Although mice are social animals, individual housing is sometimes requested after surgery. We questioned whether pair-housing mice after surgery resulted in greater trauma to the surgical site as compared with single housing. We further evaluated the effect of individual housing after surgery on the wellbeing of mice that had previously been pair-housed. Female C57Bl/6 mice (age, 6 to 8 wk) were housed as follows: group A, individually housed before and after surgery (n = 10; all 10 mice underwent surgery); group B, pair-housed before surgery but individually housed after surgery (n = 10; all 10 mice received surgery); group C, pair-housed before and after surgery (n = 20; 10 mice underwent surgery but their cage mates did not); and group D, pair-housed before and after surgery (n = 10; all 10 mice underwent surgery). Dependent variables were body weight, body condition, grimace based on real-time scoring, nest building, time to incorporate into nest test (TINT) score, wound trauma score, and missing wound clips. Weight was significantly different between groups A and C both before and after surgery. Mean nest building scores were significantly higher for pair-housed (groups C and D) than for individually housed mice (groups A and B) after surgery while TINT scores were significantly higher for these same groups both before and after surgery. Mean values for body condition, grimace score, wound score, and number of wound clips missing did not differ significantly between any groups either before or after surgery. Taken together, these results suggest that pair housing mice after surgery benefited their wellbeing but did not increase trauma to the surgical incision site or disturb wound clips as compared with individually housed mice. Furthermore, separating previously pair-housed mice (group B) did not affect these measures as compared with individually housed mice (Group A) either before or after surgery.