Factors Affacting the Diabetic Models Induced by Streptozocin in SD and Wistar Rats

Objective To investigate the effects of streptozocin(STZ) dosage,STZ administration way and the strains of rats on the incidence and mortality of type 1 diabetes.At the same time,to study the value of oral glucose tolerance test(OGTT) for making an estimate of the incidence of diabetes mellitus.Methods ①Wistar rats were divided into high-dose groups(STZ,65 mg/kg) and moderate-dose groups(STZ,55 mg/kg).②Compare with Wistar rats,SD rats were injected intraperitoneally with moderate dose STZ(STZ,55 mg/kg).③SD rats were divided into two groups.The rats in one group were in a single injection.The other group was injected twice(55 mg/kg on the first day and 55 mg/kg on the eighth day),the OGTT was detected once in observation periods.The incidence and mortality of diabetes model were measured.Result ① The incidence and mortality of Wistar rats were higher than that of SD rats.② Injecting twice could increase the incidence of diabetes rats and reduce the mortality.③ The positive rate of abnormal OGTT was significantly higher than the positive rate of abnormal fasting blood glucose in the diabetic model rats whose pancreas had definite pathologic change.Conclusion The animal diabetes model induced by streptozocin is steady and reliable.The incidence and mortality of diabetes model of Wistar rats are higher than those of SD rats.Using SD rats,moderate dose STZ and injecting twice may increase the incidence of diabetes model and reduce the mortality.During animal experiment,OGTT has a better value than fasting blood glucose for making an estimate of the incidence of diabetes mellitus.Using OGTT can avoid missing diagnosis.