D.Yu. Akimov1, M.N. Makarova2, S.V. Gushchina3, S.O. Han4, P.D. Shabanov5

1–4 Research and manufacturing company “Home of Pharmacy” (Leningrad region, Vsevolozhsky district, Kuzmolovsky settlement, Russia)

1,5 FSBSI “Institute of Experimental Medicine” (Saint-Petersburg, Russia)

1 akimov.du@doclinika.ru, 2 makarova.mn@doclinika.ru, 3 guschina.sv@doclinika.ru, 4 han.so@doclinika.ru, 5 shabanov.pd@iemspb.ru

Due to their accessibility and ease of handling, rabbits have become widespread during preclinical studies. A number of studies conducted on rabbits require their anesthesia in order to ensure their fixation (for example, to remove blood pressure, ECG) or adequate anesthetic support associated with surgical intervention (wound suturing, sensor stitching, tendon cutting, etc.). The most commonly used drugs when manipulating rabbits in Russia are xylazine and (tiletamine + zolazepam) as well as their combination.

The article presents data on the effect of a combination of xylazine and (tiletamine + zolazepam) in various doses on the duration of anesthesia, electrocardiography, blood pressure, respiratory rate, heart rate, saturation, hematological blood parameters, hemostasis system and biochemical profile in rabbits.

The aim of this study was to evaluate the effect of a combination of xylazine and (tiletamine + zolazepam) in different doses on some indicators in rabbits.

The study was conducted on the basis of Research and manufacturing company “Home оf Pharmacy”. The research plan was approved at the meeting of the bioethical commission, conclusion No. 2.31/20. In this study, New Zealand rabbits aged 16-22 weeks were used as test systems. The range of body weight at the time of administration (M±SD): 4035±261 g. 3 groups of animals were formed with 10 rabbits (5 males, 5 females) in each group. Another 1 female and 1 male were available after the formation of experimental groups in case a replacement was needed. During the experiment and during the adaptation period, the animals were kept in individual cages, the floor area and environmental conditions corresponded to Directive 2010/63/EC. Feeding and watering was carried out twice. Feed PK-90, manufacturer "Tosnensky feed mill". Before weighing and before the introduction of the tested objects, the animals were subjected to feed and water deprivation for no more than 4 and 2 hours, respectively.

Investigated objects: xylazine (2,5/3,5/5 mg/kg) was administered intramuscularly, after which tiletamine+zolazepam was administered intravenously (5/7,5/10 mg/kg). The degree of anesthesia was determined by the ball system based on reflexes. The duration of anesthesia was recorded from the moment of extinction of reflexes to their manifestation. Electrocardiography and heart rate were recorded using "Poly-spectrum-8/E". Blood pressure was recorded with the equipment "Zoomed BPM-1". The frequency of respiratory movements per minute was determined by counting the movements of the chest. Saturation – "Zoomed IM-10". Blood tests were carried out by automatic and semi-automatic methods according to the generally accepted methodology. Statistical processing was carried out on GraphPad Prism software.

Based on the study, there is a clear dose-dependent effect of the combination of xylazine and (tiletamine + zolazepam) on the duration of anesthesia. When conducting and analyzing an ECG, the effect on the interval of PQ, ST-segment and QT was found in both males and females. There is a dose-dependent decrease in systolic pressure, BPD and heart rate. The use of the studied combination in various doses did not have a significant effect on saturation, general clinical blood analysis, hemostasis, most biochemical parameters except for creatinine and urea levels, which increased. The results obtained may be useful for preclinical studies in differentiating changes associated with the use of anesthesia from changes associated with other interventions.

Akimov D.Yu., Makarova M.N., Gushchina S.V., Han S.O., Shabanov P.D. The effect of the combination of xylazine with tiletamine + zolazepam upon reaching different depths of anesthesia on some indicators in rabbits. Technologies of Living Systems. 2024. V. 21.
№ 1. Р. 63-74. DOI: https://doi.org/10.18127/j20700997-202401-06 (In Russian)

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