The role of transforming growth factor-β 2 and 3 in formation of ventral body wall in the cadmium-induced omphalocele chick model

PurposeIn the chick embryo, the administration of cadmium (Cd) induces ventral body wall defects (VBWDs) similar to the human omphalocele. Transforming growth factors β (TGFs-β) are involved in many developmental processes, including ventral body wall formation. The Tgfβ2−/− Tgfβ3−/− double knockout mice and Tgfβ2−/− Tgfβ3+/− mutants show VBWD, whereas Tgfβ2+/− Tgfβ3−/− mutants display normal ventral body wall fusion. We designed this study to investigate the messenger RNA (mRNA) levels of TGF-β2 and TGF-β3 in the Cd-induced omphalocele chick model during early embryogenesis.MethodsChick embryos were exposed to either Cd or saline, harvested 1 hour (1H), 4H, and 8H after treatment and then divided into 2 groups: control and Cd (n = 8 at each time-point, respectively). Reverse transcription polymerase chain reaction was performed to evaluate the mRNA levels of TGF-β2 and TGF-β3 and statistically analyzed.ResultsThe mRNA expression levels of TGF-β2 at 1H were significantly decreased in the Cd group compared to controls (P < .05). However, the levels of TGF-β3 were not altered at all the time-points studied.ConclusionWe provide evidence, for the first time, that TGF-β2 gene expression is downregulated during a narrow window of early embryogenesis in the Cd chick model. Our data show that TGF-β2 is the key gene involved in the formation of ventral body wall.