Study On The Correlations Of Protein Tyrosine Phosphatase 1B And Gestational Diabetes Mellitus

ObjectiveTo study the expression of Protein tyrosine phosphatase 1B and Protein kinase B in placental tissues of normal and diabetic pregnant women. The relationship of both substances and the insulin resistance index was discussed, to determine the signal transduction role of PTP 1B in GDM, for the further study on the pathogenesis and treatment of GDM.MethodsThe expression of PTP 1B and Aktl was detected in placental tissues of 30 diabetic pregnant women (GDM group) and 30 normal ones (control group), with the application of immunohistochemistry (IHC). The fasting blood glucose and insulin levels were determined separately with glucose oxidase method and radioimmunoassay. The body mass indexes were gained from the body weight before pregnancy. The indexes of insulin resistance, insulin sensitivity index,β-cell function, were calculated with homeostasis model (HOMA). All relevant information was statistical analyzed.Results1 There was no statistical difference in age, gestational age, and blood pressure between two groups (P>0.05). The body mass index, fasting blood glucose, fasting insulin, glycosylated hemoglobin, insulin resistance index of GDM group were higher than those of control group (P< 0.001). While the insulin sensitivity index,βcell function of GDM group were lower than those of control group (β-cell function P< 0.01, insulin sensitivity index P<0.001).2 There was higher expression of PTP 1B positive cells in GDM group. There was significant statistical difference between the two groups (Z=-3.350, P= 0.001).3 There was less expression of Aktl positive cells in GDM group. There was significant statistical difference between the two groups (Z=-2.237, P=0.006).4 The expression of PTP IB was negatively correlated with that of Aktl in placental tissue. The correlation coefficient (rs) was-0.535 (P=0.000).5 The level of HOMA-IR was positively correlated with BMI, and the rs=0.705 (P=0.000). The expression of PTP 1B was positively correlated with HOMA-IR, and the rs=0.663 (P=0.000). The expression of Aktl was negatively correlated with HOMA-IR, and the rs=0.326 (P=0.002).Conclusions1 The level of PTP 1P is obviously higher in GDM group, and its expression is positively correlated with HOMA-IR. It can be concluded that the PTP 1P is relevant with the increase of insulin resistance.2 The level of Akt is obviously lower in GDM group, and its expression is negatively correlated with HOMA-IR. It can be concluded that the PTP 1P may result in insulin resistance by the means of inhibiting the signal transduction of Akt.3 There is more serious insulin resistance in GDM patients, in spite of the increase of insulin secretion, which cannot counteract the increase of insulin resistance. It may be the main reason for the GDM. The relation of obesity and insulin resistance is affinitive, and obesity may play an important role in the process of GDM.4 The PTP 1P is the negative regulator of insulin signal transduction. However, further study is needed to determine whether PTP 1P plays a decisive role in the development of GDM.