Comparison of the anesthetic effects of 2,2,2-tribromoethanol on ICR mice derived from three different sources / 한국실험동물학회지

This study was conducted to compare the anesthetic effects of 2,2,2-tribromoethanol (TBE, Avertin®) in ICR mice obtained from three different sources. TBE (2.5%) was intraperitoneally injected at three doses: high-dose group (500 mg/kg), intermediate-dose group (250 mg/kg), and low-dose group (125 mg/kg). Anesthesia time, recovery time, end-tidal peak CO2 (ETCO₂), mean arterial blood pressure, heart rate, oxygen saturation (SpO₂), body temperature, pH, PCO₂, and PO₂ of the arterial blood were measured. Stable anesthesia was induced by all doses of TBE and the anesthesia time was maintained exhibited dose dependency. No significant differences in anesthetic duration were found among the three different strains. However, the anesthesia time was longer in female than in male mice, and the duration of anesthesia was significantly longer in female than in male mice in the high-dose group. The recovery time was significantly longer for female than male mice in the intermediate- and high-dose groups. In the ICR strains tested, there were no significant differences in the mean arterial blood pressure, SPO₂, arterial blood PCO₂, and PO₂, which decreased after TBE anesthesia, or in heart rate and ETCO₂, which increased after TBE anesthesia. In addition, body temperature, blood biochemical markers, and histopathological changes of the liver, kidney, and lung were not significantly changed by TBE anesthesia. These results suggested that ICR mice from different sources exhibited similar overall responses to a single exposure to TBE anesthesia. In conclusion, TBE is a useful drug that can induce similar anesthetic effects in three different strains of ICR mice.

Kinetics of proinflammatory cytokines after intraperitoneal injection of tribromoethanol and a tribromoethanol/xylazine combination in ICR mice / 한국실험동물학회지

Tribromoethanol (2,2,2-tribromoethanol, TBE) is a popular injectable anesthetic agent used in mice in Korea. Our goal was to assess the risks associated with side effects (lesions) in the abdominal cavity, especially at high doses. To understand the underlying pathophysiological changes, we examined levels of cytokines through ELISA of abdominal lavage fluid and spleen collected from mice treated with low and high-dose TBE. ICR mice were anesthetized using one of the following protocols: a combination of TBE 200 mg/kg (1.25%) and xylazine 10 mg/kg; TBE 400 mg/kg (1.25%); and TBE 400 mg/kg (2.5%). Administration of high-dose TBE (400 mg/kg) increased the interleukin-1beta and interleukin-6 levels in the peritoneal cavity over the short term (<1 day) compared with sham controls and low-dose TBE (200 mg/kg) groups. Cytokine expression in the low-dose TBE group was similar to the control group, whereas in the high-dose TBE group cytokine levels were higher in abdominal lavage fluid and spleen over the long term (10 days post-injection). We conclude that a combination of TBE 200 mg/kg (1.25%) and xylazine (10 mg/kg) is a safe and effective anesthetic for use in animals.

Evaluation on Efficacy and Safety of Tribromoethanol and Tribromoethanol plus alpha2-Adrenergic Agonists in Different Mouse Strains / 한국실험동물학회지

The present study was carried out to provide a guideline for injecting tribromoethanol (TBE) as the main anesthetic agent, while adjusting the doses of xylazine (X) and medetomidine (M) according to different strains of mice (male ICR, C57BL/6, and BALB/c). Seven intraperitoneal injection anesthesia protocols using TBE and mixtures of TBE and alpha2-adrenergic agonists (TBE/X and TBE/M) were compared in terms of their efficacy and safety (anesthetic duration, death rate, and the development of pathological lesions of abdominal organs). All animals that were injected with a low dose of TBE (200 mg/kg) displayed clear signs of light anesthesia with a strong pedal withdrawal reflex. Despite the good anesthetic effect, a high dose of TBE (400 mg/kg) was not a suitable anesthetic for major surgery in all mouse strains because of the risk of pathologic changes in the abdominal organs, such as retention of the digestive tract, peritonitis, and fibrinoid adhesion. TBE200/X10 and TBE200/M0.5 (TBE, 200 mg/kg; X, 10 mg/kg; M, 0.5 mg/kg) appeared to be safe and provided satisfactory anesthesia in ICR mice. Finally, there were clear differences in anesthetic efficacy among ICR, C57BL/6, and BALB/c strains. TBE/M and TBE/X did not anesthetize BALB/c mice, and it anesthetized C57BL/6 mice for a short time. When administered with TBE/X and TBE/M maintained the sedation of ICR mice. We were able to establish different regimes for each strain (TBE200/X20 for C57BL/6, TBE300/X10 and TBE200/M1 for BALB/c). Our results showed that TBE/X and TBE/M could be recommended as an anesthetic mixture, with the dose appropriately adjusted according to mouse strain.

Evaluation on Efficacy and Safety of Tribromoethanol and Tribromoethanol plus alpha2-Adrenergic Agonists in Different Mouse Strains / 한국실험동물학회지

The present study was carried out to provide a guideline for injecting tribromoethanol (TBE) as the main anesthetic agent, while adjusting the doses of xylazine (X) and medetomidine (M) according to different strains of mice (male ICR, C57BL/6, and BALB/c). Seven intraperitoneal injection anesthesia protocols using TBE and mixtures of TBE and alpha2-adrenergic agonists (TBE/X and TBE/M) were compared in terms of their efficacy and safety (anesthetic duration, death rate, and the development of pathological lesions of abdominal organs). All animals that were injected with a low dose of TBE (200 mg/kg) displayed clear signs of light anesthesia with a strong pedal withdrawal reflex. Despite the good anesthetic effect, a high dose of TBE (400 mg/kg) was not a suitable anesthetic for major surgery in all mouse strains because of the risk of pathologic changes in the abdominal organs, such as retention of the digestive tract, peritonitis, and fibrinoid adhesion. TBE200/X10 and TBE200/M0.5 (TBE, 200 mg/kg; X, 10 mg/kg; M, 0.5 mg/kg) appeared to be safe and provided satisfactory anesthesia in ICR mice. Finally, there were clear differences in anesthetic efficacy among ICR, C57BL/6, and BALB/c strains. TBE/M and TBE/X did not anesthetize BALB/c mice, and it anesthetized C57BL/6 mice for a short time. When administered with TBE/X and TBE/M maintained the sedation of ICR mice. We were able to establish different regimes for each strain (TBE200/X20 for C57BL/6, TBE300/X10 and TBE200/M1 for BALB/c). Our results showed that TBE/X and TBE/M could be recommended as an anesthetic mixture, with the dose appropriately adjusted according to mouse strain.