Anesthetic effect of phenobarbital sodium on female BALB/c mice

Objective:Anesthetics are of great importance in avoiding severe pain and suffering in animals and ensuring experimental progress.This study was aimed at elucidating the anesthesia score of phenobarbital sodium as a general anesthetic at different concentrations and doses in BALB/c mice,and finding the suitable anesthesia strategies for experimental surgeries.Methods:Phenobarbital sodium was administrated intraperitoneally at the doses of 75,100,125,150,and 200 mg/kg and randomly in different concentrations(2%,5%,and 10%)to female BALB/c mice.The anesthesia score was evaluated based on the stimulus index including tail-pinch,front and hind limb withdrawal,and eyelid reflexes.The speed and duration of anesthesia in different groups were recorded per the occurrence and duration of the righting reflex.Results:The anesthetic effect of phenobarbital sodium on female BALB/c mice showed an obvious dose-dependency.Respiratory suppression caused by high-dose anesthesia may lead to mouse death.Based on the anesthesia score,when the phenobarbital sodium treatment was greater than or equal to five percent or 200 mg/kg,more than 80%mice meet the anesthesia depth that surgical operation needed.The rates of achieving surgical anesthesia depth(standard-reaching rate)in mice treated with 2%sodium phenobarbital were 0%in the 75 mg/kg group,0%in the 100 mg/kg group,50%in the 125 mg/kg group,66.7%in the 150 mg/kg group,and 100%in the 200 mg/kg group.The standard-reaching rate of mice treated with 5%concentration of phenobarbital sodium were:0%in the 75 mg/kg group,0%in the 100 mg/kg group,83.33%in the 125 mg/kg group,100%in the 150 mg/kg group,and 100%in the 200 mg/kg group.The standard-reaching rate of mice treated with 10%concentration of phenobarbital sodium were:50%in the 75 mg/kg group,66.7%in the 100 mg/kg group,100%in the 125 mg/kg group,100%in the 150mg/kg group,and 100%in the 200 mg/kg group.Sedation and hypnosis were induced in the low-concentration dose group,and anesthesia was induced in the high-concentration dose group.In the 5%and 125 mg/kg phenobarbital sodium groups,the mortality rate of mice was 0,the anesthesia induction time was(35.5±7.92)minutes,and the anesthesia duration was(106±39.59)minutes.In the 5%and 150 mg/kg phenobarbital sodium groups,the mortality rate of mice was 0,the anesthesia induction time was(34.83±5.27)minutes,and the anesthesia duration was(131.7±36.75)minutes.Conclusion:Phenobarbital sodium alone can provide appropriate general anesthesia in female BALB/c mice.Both the concentration and dose of phenobarbital sodium can affect the anesthetic effect.On the basis of our findings,we recommend the 5%and 125 mg/kg and 5%and 150 mg/kg concentration–dose combinations of phenobarbital sodium for anesthetizing mice according to the surgical requirement.