ALDH7A1 and fetal growth restriction: To further verify the reliability of the selected reference genes in physiology, we detect the expression of the candidate reference genes in the cartilage development of male and female rats in the PDE-induced IUGR model which is a common experimental model to study cartilage development-derived diseases (Rowas et al., 2012; Tie et al., 2016; Xie et al., 2018; Cai et al., 2019).