Methodology research of rat diabetic model induced by streptozotocin several times

Objective To explore the effect of fasting time,sex difference and low dosage streptozotocin several times on diabetic model incidence in rats.Methods After ip STZ 30 mg·kg-1 60,62 and 64 h,rats were fasted at 20,22 and 24 o'clock separately,then to detect fasting plasma glucose(FPG) at 8 o'clock next moring,to caculate the diabetic model incidence(FPG≥7.0 mmol·L-1).Female and male rats were injected STZ 30 mg·kg-1 separately,to observe the diabetic model incidence difference.The male rats were ip STZ(20,25,30,40,50 mg·kg-1)separately,after 72h,those blood glucose not up to the standard were ip STZ 20 mg·kg-1 again,to compare the incidence of diabetic model and the blood glucose level.Results The diabetic rats number of the groups fasted at 22 and 24 o'clock were double of that in the group fasted at 20 o'clock;the blood glucose of diabetic rats rose further.The male diabetic rats number was nearly double of that in female group,the blood glucose of diabetic rats rose further too.The accumulated diabetic model incidences of rats injected STZ 25,30,40 and 50 mg·kg-1 separately at the first time were higher than the group injected STZ 20 mg·kg-1 at the first time(50%),the death incidence of the group injected STZ 50 mg·kg-1 at the first time was higher than the groups injected STZ 25,30 mg·kg-1 at the first time in 6 weeks.Conclusion Before detecting FPG the best fasting time was 22~24 o'clock.The absorption of male rats to make diabetic model was better than female rats.The best method to establish diabetic model of rats with high incidence and low inciednce of death is ip STZ 25~30 mg·kg-1 at the first time,then the rats whose blood glucose was not up to the standand received ip STZ 20 mg·kg-1 again.