Reflex scoring test.

Background
The aim of our study was to test different anesthetic mixtures in order to identify the most suitable one for a surgical cardiac ischemia-reperfusion model in mice.
Methods
1) Sixty four mice were submitted to one of the 6 combinations of ketamine or alfaxalone associated to xylazine, medetomidine or midazolam. Depth and quality of anesthesia were evaluated via 5 reflex scores. 2) Impact of analgesic (buprenorphine or butorphanol), anesthesia reversal (with atipamezole) and surgery (cardiac ischemia-reperfusion surgery) have been tested in the selected protocols. 3) infarction size has been measured with TTC (Triphenyl Tetrazolium Chloride) method in mice anesthetized with best protocols.
Results
Protocol involving medetomidine induced the longest surgical anesthesia: (median = 120, {interquartile range = 100–125}) min with ketamine and 53 {25–100} min with alfaxalone. Butorphanol substitution with buprenorphine did not alter time-related anesthesia parameters. Atipamezole reversal considerably reduced both recovery and immobilization time (respectively 22 {18–30} min and 98 {88–99} min vs. 55 {40–70} min and 143 {131–149} min, in groups with no reversal, p = 0.001) with no impact on infarction size measurement.
Conclusion
In this study, the combination alfaxalone/medetomidine/buprenorphine (80/0,3/0,075 mg.kg-1, s.c.) associated with reversal by atipamezole was a reliable anesthetic protocol for murine surgery, particularly for the study of ischemia-reperfusion.