摘要
2,3,7,8-四氯-二苯基-对-二恶英(2,3,7,8-tetrachlorodibenzo-p-dioxin,TCDD)为毒性 很强的环境污染物质。用O-1．0μg／L的TCDD处理受精后24 h(24 hpf)的斑马鱼胚至观察时为止,进行了形 态学观察、基因阻断、原位杂交、TUNEL染色以及免疫学染色等实验。结果表明,TCDD处理后会引起斑马鱼 下颌短小,Shh基因在下颌部表达降低;而在芳烃基受体AhR功能阻断的胚胎中,TCDD并没有引起斑马鱼下 颌短小,同时也没有观察到Shh基因表达缺失;免疫学染色表明TCDD和Shh阻断物质Cyclopamine均可引起 斑马鱼下颌区域增殖细胞的减少。TCDD引起的下颌短小可能是首先引起以AhR为媒介的Shh表达缺失,进而 造成下颌部增殖细胞减少。
2, 3, 7, 8-tetrachlorodibenzo-p-dioxin （TCDD） is one of the most toxic environmental pollutants. The goal of this study is to understand the cause of the short lower jaw induced by TCDD in the zebrafish embryos. Embryos are exposed to TCDD （0-1.0μg/l,） at 24 h post fertilization （24 hpf） until the time of observation and studied by gene knockdown, immunohistochemistry staining and in situ hybridization. The results show that TCDD treatment leads to de- creases in the size of the lower jaw and reduced Shh gene expression. This effect can be blocked by injection of Morpholino antisense oligos against AhR2, the potential TCDD receptor. We also find Cyclopamine, a Shh inhibitor, caused short lower jaw and decreased cell proliferation in the zebrafish embryos. These results suggest that TCDD might inhibit the expression of Shh through AhR and lead to decreased cell proliferation and short lower jaw in zebrafish embryos.
基金
国家自然科学基金项目(30360090)
教育部新世纪优秀人才支持汁划(NCET-04-0262)
