使用野生型、表皮生长因子（EGF）基因敲除和转化生长因子-α（TGFα）基因敲除小鼠品系，在无血清器官培养中，表皮生长因子（EGF）、转化生长因子-α（TGFα）和2,3,7,8-四氯二苯并对二恶英对胚胎腭融合的影响。

Effects of epidermal growth factor (EGF), transforming growth factor-alpha (TGFalpha), and 2,3,7,8-tetrachlorodibenzo-p-dioxin on fusion of embryonic palates in serum-free organ culture using wild-type, EGF knockout, and TGFalpha knockout mouse strains.

作者信息

Abbott Barbara D, Buckalew Angela R, Leffler Korin E

机构信息

Reproductive Toxicology Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA.

出版信息

Birth Defects Res A Clin Mol Teratol. 2005 Jun;73(6):447-54. doi: 10.1002/bdra.20133.

DOI:10.1002/bdra.20133

PMID:15880701

Abstract

BACKGROUND

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is teratogenic in mice, producing cleft palate (CP). TCDD exposure disrupts expression of epidermal growth factor (EGF) receptor, EGF, and transforming growth factor-alpha (TGFalpha) in the palate and affects proliferation and differentiation of medial epithelial cells. EGF knockout embryos are less susceptible to the induction of CP by TCDD. This study used palate organ culture to examine the hypothesis that EGF enables a response to TCDD.

METHODS

The midfacial tissues from wild-type (WT), EGF knockout, C57BL/6J, and TGFalpha knockout embryos were placed in organ culture on gestational day (GD) 12. Palatal explants were cultured for 4 days in serum-free Bigger's (BGJ) medium with 0.1% dimethyl sulfoxide (DMSO) or 1 x 10(-8) M TCDD with or without 2 ng of EGF/ml, 1 or 2 ng of TGFalpha/ml. Effects on palatal fusion were evaluated on day 4 of culture. EGF levels in explants and medium were determined using Luminex technology.

RESULTS

In serum-free, control medium, palates from all of the strains fused. EGF knockout palates cultured with TCDD (no EGF) fused, but those cultured with TCDD + 2 ng of EGF/ml failed to fuse (p < 0.05 vs. control or TCDD without EGF). TGFalpha knockout palates failed to fuse when cultured with TCDD + 2 ng of TGFalpha/ml. EGF levels increased in tissue and accumulated in the medium after 24 hr of culture.

CONCLUSIONS

This study demonstrated that providing EGF to the palates of EGF knockout mice restored the response to TCDD. These studies support the hypothesis that the mechanism for induction of CP by TCDD is mediated via the EGFR pathway.

摘要

背景

2,3,7,8-四氯二苯并-对-二噁英（TCDD）对小鼠具有致畸性，可导致腭裂（CP）。TCDD暴露会扰乱腭部表皮生长因子（EGF）受体、EGF和转化生长因子-α（TGFα）的表达，并影响内侧上皮细胞的增殖和分化。EGF基因敲除胚胎对TCDD诱导的CP敏感性较低。本研究采用腭器官培养来检验EGF促成对TCDD产生反应这一假说。

方法

在妊娠第12天，将野生型（WT）、EGF基因敲除、C57BL/6J和TGFα基因敲除胚胎的面中部组织置于器官培养中。腭部外植体在含有0.1%二甲基亚砜（DMSO）或1×10⁻⁸ M TCDD的无血清Bigger氏（BGJ）培养基中培养4天，培养基中添加或不添加2 ng/ml的EGF、1 ng/ml或2 ng/ml的TGFα。在培养第4天评估对腭融合的影响。使用Luminex技术测定外植体和培养基中的EGF水平。

结果

在无血清对照培养基中，所有品系的腭部均发生融合。用TCDD（无EGF）培养的EGF基因敲除腭部发生融合，但用TCDD + 2 ng/ml EGF培养的腭部未发生融合（与对照或无EGF的TCDD相比，p < 0.05）。用TCDD + 2 ng/ml TGFα培养时，TGFα基因敲除腭部未发生融合。培养24小时后，组织中的EGF水平升高并在培养基中积累。