Internal Medicine of Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030 People's Republic of China.
Tongji Wenchang Hospital, Huazhong University of Science and Technology, Wenchang, 571321 People's Republic of China.
Mol Autism. 2017 Aug 17;8:46. doi: 10.1186/s13229-017-0159-3. eCollection 2017.
Autism spectrum disorder (ASD) is characterized by impairments in social communication and restricted or repetitive behaviors or interests. ASD is now diagnosed in more than one out of 100 children and is biased towards males by a ratio of at least 4:1. Many possible explanations and potential causative factors have been reported, such as genetics, sex, and environmental factors, although the detailed mechanisms of ASD remain unclear.
The dams were exposed through oral contraceptives to either vehicle control (VEH) alone, levonorgestrel (LNG) alone, ethinyl estradiol (EE) alone, or a combination of LNG/EE for 21 days during their pregnancy. The subsequent 10-week-old offspring were used for autism-like behavior testing, and the limbic tissues were isolated for analysis. In another experimental group, 8-week-old male offspring were treated by infusion of ERβ overexpression/knockdown lentivirus in the amygdala, and the offspring were analyzed after 2 weeks.
We show that prenatal exposure of either LNG alone or a LNG/EE combination, but not EE alone, results in suppression of ERβ (estrogen receptor β) and its target genes in the amygdala with autism-like behavior in male offspring, while there is a much smaller effect on female offspring. However, we find that there is no effect on the hippocampus and hypothalamus. Further investigation shows that ERβ suppression is due to LNG-mediated altered methylation on the ERβ promoter and results in tissue damage with oxidative stress and the dysfunction of mitochondria and fatty acid metabolism, which subsequently triggers autism-like behavior. Overexpression of ERβ in the amygdala completely restores LNG-induced ERβ suppression and autism-like behaviors in offspring, while ERβ knockdown mimics this effect, indicating that ERβ expression in the amygdala plays an important role in autism-like behavior development.
We conclude that prenatal levonorgestrel exposure induces autism-like behavior in offspring through ERβ suppression in the amygdala. To our knowledge, this is the first time the potential effect of oral contraceptives on the contribution of autism-like behavior in offspring has been discovered.
自闭症谱系障碍（ASD）的特征是社交沟通障碍和受限或重复的行为或兴趣。现在，每 100 名儿童中就有超过 1 名被诊断出患有 ASD，而且男女比例至少为 4:1。已经报道了许多可能的解释和潜在的致病因素，例如遗传、性别和环境因素，尽管 ASD 的详细机制仍不清楚。
在怀孕期间，通过口服避孕药使母鼠单独暴露于载体对照（VEH）、左炔诺孕酮（LNG）、乙炔雌二醇（EE）或 LNG/EE 联合 21 天。随后，10 周龄的后代用于自闭症样行为测试，并分离其边缘组织进行分析。在另一个实验组中，8 周龄的雄性后代通过在杏仁核中输注 ERβ过表达/敲低慢病毒进行处理，两周后对后代进行分析。
我们表明，单独暴露于 LNG 或 LNG/EE 联合，而不是 EE 单独，会导致雄性后代的杏仁核中 ERβ（雌激素受体β）及其靶基因受到抑制，并伴有自闭症样行为，而对雌性后代的影响要小得多。然而，我们发现这种影响在海马体和下丘脑不存在。进一步的研究表明，ERβ的抑制是由于 LNG 介导的 ERβ启动子上的甲基化改变所致，导致组织损伤、氧化应激以及线粒体和脂肪酸代谢功能障碍，随后引发自闭症样行为。在杏仁核中过表达 ERβ可完全恢复 LNG 诱导的 ERβ抑制和后代的自闭症样行为，而 ERβ 敲低则模拟了这种作用，表明 ERβ 在杏仁核中的表达在自闭症样行为的发展中起着重要作用。
我们得出结论，左炔诺孕酮暴露会通过 ERβ 在杏仁核中的抑制导致后代出现自闭症样行为。据我们所知，这是首次发现口服避孕药对后代自闭症样行为的潜在影响。
