Comparing the Rat Grimace Scale and a composite behaviour score in rats

Area of Science:

• Veterinary Medicine
• Animal Behavior
• Pain Research

Background:

• Assessing pain in laboratory animals is crucial for welfare and research.
• The Rat Grimace Scale (RGS) and Composite Behaviour Score (CBS) are promising behavioral pain assessment tools in rats.
• Direct comparison of RGS and CBS, and their response to analgesics, is limited.

Purpose of the Study:

• To compare the sensitivity of RGS and CBS in a rat laparotomy model.
• To evaluate the temporal and analgesic effects of meloxicam and buprenorphine on RGS and CBS.
• To determine if these behavioral scales discriminate analgesic efficacy.

Main Methods:

• Female Wistar and Sprague Dawley rats (n=52) were randomized to saline, meloxicam, or buprenorphine treatment.
• Laparotomy was performed, and rats were video-recorded pre- and post-operatively.
• Videos were assessed using both RGS and CBS by a blinded observer at multiple time points.

Main Results:

• Both CBS and RGS scores significantly increased post-laparotomy in the saline group.
• Meloxicam and buprenorphine reduced CBS scores to baseline.
• Only buprenorphine significantly reduced RGS scores; meloxicam did not alter RGS compared to saline.

Conclusions:

• CBS and RGS exhibit differential sensitivity in detecting analgesic effects in rats.
• CBS appears more sensitive to the analgesic effects of both meloxicam and buprenorphine.
• RGS may be less responsive to certain analgesics like meloxicam in this model.