Skeletal Muscle Insulin Resistance in a Novel Fetal Growth Restriction Model

The abnormal fetal environment exerts long-term effects on skeletal muscle, and fetal growth restriction (FGR) is associated with insulin resistance in adulthood. In this study, we examined insulin resistance in early adulthood and insulin signaling in skeletal muscle using a novel FGR rat model. Ameroid constrictors (AC) were placed on the bilateral uterine and ovarian arteries of rats on day 17 of gestation; placebo surgery was performed on the control group. We measured body weight at birth, 4, 8, and 12 weeks of age and performed oral glucose tolerance tests at 8 and 12 weeks. Rats were dissected at 12 weeks of age. We examined the mRNA and protein expression of insulin signaling pathway molecules in skeletal muscle. FGR rats had a significantly lower birth weight than control rats (p = 0.002). At 12 weeks of age, the incremental area under the curve of blood glucose was significantly higher, and GLUT4 mRNA and protein expression in soleus muscle was significantly lower in the FGR group than in the control group. Reduced placental blood flow in the AC-attached FGR group caused insulin resistance and altered insulin signaling in skeletal muscles. Therefore, FGR causes skeletal muscle insulin resistance in early adulthood.