Relationship between Gab1 expression in placenta and neonatal birth weight in gestational diabetes mellitus

Abstract

Objective To evaluate the relationship between placental expression of Gab1 and neonatal birth weight in mothers with gestational diabetes mellitus (GDM). Methods From the singleton and full-term cesarean delivered women in Shengjing Hospital Affiliated to China Medical University between October 2014 and May 2015, 30 macrosomia babies with maternal GDM were selected as GDM macrosomia group, 30 cases of GDM with normal neonatal birth weight as GDM normal group, 30 cases without GDM but with macrosomia as normal macrosomia group, and 30 cases without GDM and with normal neonatal birth weight as the normal control group. Gab1 protein and mRNA expression in placentas were detected using immunohistochemistry, Western blot and real-time quantitative-polymerase chain reaction. Analysis of variance, LSD, Dunnett's T3, Chi-square test and Pearson's correlation analysis were used for statistical analysis. Results (1) Gab1 protein location and positive expression rate: Gab1 protein expression in human placenta tissue was located in the nucleus. The positive epression rate of Gab 1 protein in the GDM macrosomia group was higher than in the GDM normal group and normal macrosomia group [93%(28/30), 73%(22/30) vs 73%(22/30)] and those in the normal macrosomia group and GDM normal group were higher than in the normal control group[47%(14/30)](χ2=4.320, 4.320, 4.444 and 4.444, all P<0.05). (2) The expression levels of Gab1 protein and mRNA: The expression level of Gab1 protein in the GDM macrosomia group was higher than in the GDM normal group and normal macrosomia group (1.43±0.58 vs 1.05±0.67 and 0.95±0.59), and that in the normal macrosomia group and GDM normal group were higher than in the normal control group (0.64±0.38) (LSD test, all P<0.05). The expression levels of Gab1 mRNA showed the same trend as the expression levels of Gab1 protein in the four groups. (3) Gab1 protein expression level was positively associated with neonatal birth weight (r=0.320, P=0.320). Conclusions The expression of Gab1 in placenta is involved in the regulation of birth weight in GDM mothers. Key words: Diabetes, gestational; Placenta; Adaptor proteins, signal transducing; Birth weight; Fetal macrosomia