Comparison of different dosage of streptozotocin-induced gestational diabetes mellitus on rats

AIM:To explore the effect of the stability of the rat model of gestational diabetes mellitus(GDM)by different dosage of streptozocin(STZ),for the research on maternal and fetal GDM provide experimental basis.METHODS:Forty-six Sprague-Dawley pregnant rats were selected and randomly assigned into 4 groups(the low doses group,the medium doses group,the high doses group and the control group).The rats were injected respec-tively with STZ(35,45,60 mg/kg)or equal dosage of citrate buffer solution intraperitoneally according to their assigned groups.Their fasting blood glucose were measured after STZ injection 3,9,14 and 19 d later.During the whole gestation period,the body weights,amount of drinking water,food consumption and urine volume of these rats were tested.Draw a comparison about the modeling rate,turning negative rate and mortality rate in the different groups.The rats in all groups underwent dissection at their gestational ages of 19 d to obtain the pancreatic tissue for pathological study by HE staining.RESULTS:The pregnant rats of the 45 mg/kggroup showed significant signs of polyuria,polydipsia,hyperphagia and weight loss after STZ injection.It has the highest making model success rate of 83.3% and the lowest turning negative rate.There was statistically significant difference between the medium doses group and the control group in the level of fasting blood glucose[(21.8±3.0)vs(5.9±1.2)mmol/L,P0.05].The body weight of the medium doses group was also lower than that in control group.The state of hyperglycemia retained longer time and steadily.CONCLUSION:The optimum dose to establish an idealexperimental animal model of streptozotocin-induced GDM is injected STZ 45 mg/kg intraperitoneally with the best stability.