A Comparative Analysis of Dexmedetomidine, Medetomidine, and Xylazine in Combination with Ketamine in Rats

This study compared the anesthetic efficacy and safety of three α₂-adrenergic agonists, xylazine, medetomidine, and dexmedetomidine, each combined with ketamine. The objective was to identify an optimal anesthetic protocol that ensures animal welfare and reliability in laboratory research. Forty male rats were separated into four groups: a control group (CO) given saline, and three treatment groups receiving ketamine 50 mg/kg combined with either 0.1 mg/kg dexmedetomidine (DK), 0.5 mg/kg medetomidine (MK), or 5 mg/kg xylazine (XK) via intraperitoneal injection. The study evaluated anesthesia profiles and physiological parameters during the procedure, while biochemical, renal, and hepatic biomarkers were evaluated after 14 consecutive days. The XK group showed a significantly longer induction time compared to the MK and DK. Correspondingly, maintenance of anesthesia was prolonged in the XK and MK groups compared to the DK group. Physiological assessments revealed significant cardiorespiratory depression in the XK group, marked by pronounced reductions in heart rate, respiratory rate, SpO2, and body temperature. In contrast, the MK and DK groups maintained more stable physiological parameters. Biochemical analysis showed minimal hepatic and renal disturbances in the DK group, with the lowest levels of liver enzymes (ALT, AST, and GGT). The XK group exhibited significantly elevated bile acids, creatine kinase, and electrolyte imbalances. Renal profiles highlighted superior clearance in the DK group. In conclusion, the DK protocol provided rapid induction, stable cardiorespiratory function, and minimal metabolic and organ disturbances. This exceptional safety profile and physiological stability make it an ideal anesthetic regimen for both laboratory and veterinary applications.