ABSTRACT
Objective To learn the injury severity and the possible mechanism of the thyroid tissue of DM rats with different levels of glucose levels. Methods Firstly,20 Wistar rats were treated with STZ to create the experimental diabetic rats models. Then,the DM rats were divided into two groups including the persistence hyperglycemia group(n = 10),and blood glucose fluctuation group(n = 10). Another 10 Wistar rats were treated as the control group. Rats were sacrificed after 12 week treatment. The bilateral thyroid were weighted and the blood biochemistry tests were conducted for detecting glucose level,lipid levels,and thyroid functions. The ultra - structure of thyroid tissue was observed using electron microscope. Results The MBG,LAGE,and SDBG of blood glucose fluctuation group and the persistence hyperglycemia group were all higher than the control group(P ﹤ 0. 05). The MBG of blood glucose fluctuation group were lower than the persistence hyperglycemia group(P ﹤ 0. 05),the SDBG and LAGE were higher than the persistence hyperglycemia group(P ﹤ 0. 05). The TC,FPG,and HbA1c levels of DM rats were significantly higher in blood glucose fluctuation group than in control group(P ﹤ 0. 05). TC ,FPG and TG levels of the DM rats in blood glucose fluctuation group were significantly lower than the rats in persistence hyperglycemia group(P ﹤ 0. 05). No significance of the free T3 and free T4 levels was observed between the diabetes rats in persistence hyperglycemia group and blood glucose fluctuation group. However,the free T3 and T4 levels were significantly lower in both model groups than in control group(P ﹤ 0. 05). The injury of follicular epithelial cells and loss of microvilli were observed in diabetes rats in both the hyperglycemia group and blood glucose fluctuation group. Conclusion The ultra - structure changes of thyroid gland tissues indicated that abnormal glucose and lipid metabolism could result in thyroid gland tissue injury,which is the potential mechanism. However,no difference of the thyroid function and ultra - structure were observed between the hyperglycemia group and blood glucose fluctuation group.