Strain and sex influence on pain sensitivity after plantar incision in the mouse.
BACKGROUND
A small surgical incision in mouse glabrous hind-paw skin induces short-lasting guarding behavior and mechanical and heat hyperalgesia-like behaviors, which imitate human postoperative pain. The increasing popularity of this animal model in drug discovery necessitates the understanding of genetic and sex influence on this animal model.


METHODS
The authors examined pain behaviors on DBA2, C57Bl/6, and 129X1/SvJ mice and male and female DBA2 mice before and after plantar incision.


RESULTS
The baseline nociceptive responses of these strains were similar, with a few exceptions. Heat responses were different between DBA2 and C57Bl/6 mice, and responses to one filament, 14.0 mN, were intermittently different. Sex did not greatly influence baseline responses. After plantar incision, these three strains of mice were not different in the development of guarding behaviors. Heat responses were only different on postincision day 3 (129X1/SvJ vs. C57Bl/6 mice); otherwise, they were the same. The responses to the series of von Frey filaments were the same after incision in the three strains. Sex did not influence incision-induced pain behaviors in DBA2 mice.


CONCLUSIONS
Although several studies postulated that mouse strain influences pain models, the authors' data indicate that such influence on incisional pain is negligible. This suggests that studies using an incision and knockout mice resulting from 129 strain mutation in a C57BL/6 strain background should have modest influence. The lack of sex differences in incisional pain may encourage researchers to use both male and female subjects in their studies.
Banik
Ratan K
RK
Department of Anesthesia, 3000 ML, University of Iowa Hospitals and Clinics, Iowa City, Iowa 52242, USA. ratan-banik@uiowa.edu
Woo
Young Cheol
YC
Park
Soo Seog
SS
Brennan
Timothy J
TJ
D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D005260:Female; D018409:Foot Injuries / Q000150:complications*; D006358:Hot Temperature; D006930:Hyperalgesia / Q000523:psychology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D010146:Pain / Q000209:etiology / Q000523:psychology*; D010147:Pain Measurement; D010812:Physical Stimulation; D012727:Sex Characteristics; D013045:Species Specificity