title: Subcutaneous Compared with Intraperitoneal KetamineXylazine for Anesthesia of Mice.
abstract: Mice are commonly anesthetized intraperitoneally with a ketamine-xylazine (KX) solution. Although this route of administration allows rapid uptake of the injected drugs, its disadvantages and potential risks include pain, peritoneal irritation, and perforation of an abdominal organ; some of the risks depend on the operator's experience. We compared the efficacy of intraperitoneal and subcutaneous administration of KX in HSD:ICR, BALB/cOlaHsd, and C57BL/6JOlaHsd mice in terms of time to onset and duration of surgical anesthesia, procedure safety, and mortality. Male and female mice (n = 20 each sex and strain) were anesthetized by using the same dose of intraperitoneal or subcutaneous KX. Time to onset and duration of immobilization and time to onset and duration of surgical anesthesia according to the pedal reflex differed significantly between strains. Within each strain, the durations of immobilization and surgical anesthesia were comparable between the routes of administration. The sex of the mouse but not the route of administration influenced whether surgical anesthesia was achieved. None of the subcutaneously-injected mice died. After intraperitoneal injections, 30% of the female mice died, compared with 3% of the male. In addition, fewer female mice achieved surgical anesthesia, suggesting a narrow therapeutic window for intraperitoneal KX in female mice. In conclusion, surgical anesthesia of mice with subcutaneous KX (K, 191.25 mg/kg; X, 4.25 mg/kg) seems to be safe, and the subcutaneous route is generally just as effective as the intraperitoneal route. The variability among mouse strains and between sexes requires further investigation to determine the optimal dosage.
authors.affiliation: Veterinary Service Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Maya
authors.initials: M
authors.lastname: Levin-Arama
authors.affiliation: Veterinary Service Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Lital
authors.initials: L
authors.lastname: Abraham
authors.affiliation: Animal Facilities, Israel Institute for Biological Research, Ness Ziona, Israel.
authors.forename: Trevor
authors.initials: T
authors.lastname: Waner
authors.affiliation: Department of Veterinary Resources, The Weizmann Institute of Science, Rehovot, Israel.
authors.forename: Alon
authors.initials: A
authors.lastname: Harmelin
authors.affiliation: Department of Statistics and Operations Research, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv, Israel.
authors.forename: David M
authors.initials: DM
authors.lastname: Steinberg
authors.affiliation: Department of Statistics and Operations Research, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Tal
authors.initials: T
authors.lastname: Lahav
authors.affiliation: Veterinary Service Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel;, Email: mickey@post.tau.ac.il.
authors.forename: Mickey
authors.initials: M
authors.lastname: Harlev
mesh_terms: D000777:Anesthetics / Q000008:administration & dosage*; D000827:Animal Welfare; D000818:Animals; D000830:Animals, Laboratory; D005260:Female; D007274:Injections, Intraperitoneal; D007279:Injections, Subcutaneous; D007649:Ketamine / Q000008:administration & dosage*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008813:Mice, Inbred ICR; D012018:Reflex; D014991:Xylazine / Q000008:administration & dosage*
chemical_list: D000777:Anesthetics; D014991:Xylazine; D007649:Ketamine