Purpose: Omphalocele is one of the most common ventral body wall defects in humans. In chick embryos, administration of the heavy metal cadmium (Cd) after 60-hour incubation induces the ventral body wall defect (VBWD), a similar event that manifests in human omphaloceles. We have previously reported that the earliest detectable histological changes in the Cd-induced chick model are observed 4 hours posttreatment. However, the exact mechanism by which Cd acts in early embryogenesis still remains unclear. The transcription factor AP-2α null mice has been shown to cause VBWD. We hypothesized that Cd-induced VBWD results from downregulation of AP-2α gene expression during the critical period of embryogenesis. Methods: Chick embryos were harvested 1 hour (1 H), 4 H and 8 H after treatment with cadmium and divided into control and Cd (n=8 at each time point) groups. Total mRNA extraction and real-time RT-PCR was performed to evaluate the mRNA expression levels of AP-2α in the Cd-induced VBWD. Differences between the two groups at each time point were analyzed statistically and statistical significance was accepted for differences where p<0.05. Results: The relative mRNA expression level of AP-2α at 4 H was significantly (p<0.05) decreased in the Cd group (1.84±2.72) compared to controls (4.08±1.36). However, the gene expression levels of AP-2α at 1 H and 8 H were not significantly different between the Cd and control groups. Conclusions: Our results provide evidence for the first time that the gene expression of AP-2α is downregulated 4 hours after treatment in the Cd-induced VBWD chick model. We speculate that the downregulation of AP-2α gene expression during this narrow window of embryogenesis may have caused VBWD.
症例は9歳女児.3点式シートベルト着用にて助手席後部に乗車中,正面より電柱に衝突し救急搬送された.精査にて膵挫滅と十二指腸水平脚の損傷が疑われた.明らかな主膵管の損傷や消化管穿孔の所見はなく,保存的治療を行い,第40病日に退院した.本症例は膵鉤部,十二指腸水平脚の限局性の損傷であり,受傷機転は,シートベルトと椎体間の圧迫によるものと考えられた.小児外傷性膵損傷の受傷機転は自転車のhandle bar injuryが特徴的とされ,シートベルトに起因する報告例は稀である.本症例ではジュニアシートではなく,大人用のシートベルトを装着していた事で,適切な位置にシートベルトが装着されていなかった可能性があり,受傷原因と考えられた.シートベルトの適切な使用を警鐘するという点においても貴重な症例と考えられたため,報告した.