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Updated: May 20, 2026
Long-term Behavioral and Reproductive Consequences of Embryonic Exposure to Low-dose Toxicants
Published on: March 6, 2018
Effects of bisphenol A on the development of central immune organs of specific-pathogen-free chick embryos
Jijing Tian1, Dongmei Luo, Ruiping She
11Department of Veterinary Pathology, Key Laboratory of Zoonosis of Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing, China.
Insights
Bisphenol A (BPA) exposure significantly harms developing chick immune organs. This study found low-dose BPA reduced bursa weight and follicle numbers, and thinned thymus cortex and medulla, confirming its direct toxicity.
Area of Science:
- Developmental toxicology
- Immunology
- Environmental health
Background:
- Bisphenol A (BPA) is an endocrine-disrupting chemical widely used in food packaging.
- Concerns exist regarding BPA's developmental toxicity, particularly in fetuses.
- The impact of BPA on immune system development requires further investigation.
Purpose of the Study:
- To investigate the effects of Bisphenol A (BPA) on the development of central immune organs in chick embryos.
- To assess histopathological changes in the thymus and bursa of Fabricius following BPA exposure.
Main Methods:
- Specific-pathogen-free (SPF) chick embryos were exposed to BPA (250 μg/egg), saline, or corn oil on embryonic day 9.
- Thymuses and bursae of Fabricius were collected on embryonic day 22 for analysis.
- Histopathological examination was performed using light microscopy and scanning electron microscopy (SEM).
Main Results:
- BPA exposure significantly reduced the weight index and lymphatic follicle count in the bursa of Fabricius (p < 0.01).
- A significant reduction in thymus cortex and medulla thickness was observed in BPA-exposed embryos (p < 0.01).
- Microscopic and SEM analyses revealed damage to lymphatic follicles and epithelial cells in both the bursa of Fabricius and thymus.
Conclusions:
- This study confirms the direct toxicity of low-dose Bisphenol A (BPA) on the development of central immune organs in chick embryos.
- BPA exposure negatively impacts the structural integrity and development of the thymus and bursa of Fabricius.
- Further research is needed to elucidate the specific mechanisms underlying BPA's immunotoxic effects.
Abstract:
Bisphenol A (BPA) is a chemical estrogen widely used in the food packaging industry, especially in baby bottles. Its toxicity for the fetus has become a great concern in recent years. In the present study, the effects of BPA on the development of central immune organs in chick embryos were investigated. A total of 30 specific-pathogen-free (SPF) chick embryos were divided into BPA, control, and vehicle group. Chick embryos were exposed to BPA (250 μg per egg), saline (control), or corn oil (vehicle) on embryonic day 9 (ED9) by injection into the allantoic cavity. Thymuses and bursae of Fabricius were collected on ED22. The microscopic examination of tissue structure and ultrastructure was carried out for histopathological changes of thymus and the bursa of Fabricius morphology under light and scanning electron microscopes (SEM). In the BPA group, the weight index of the bursae of Fabricius was significantly reduced (p < 0.01); the number of lymphatic follicles in the bursae of Fabricius was remarkably decreased (p < 0.01); and the thickness of the thymus cortex and medulla was reduced (p < 0.01). Light microscope and SEM examinations further showed that the lymphatic follicles and epithelial cells of the bursa of Fabricius and thymus were damaged by BPA. Our study confirms a direct toxicity of BPA at a very low-dose level on the development of the central immune organs of SPF chick embryos. However, more studies are necessary to elucidate the underlying mechanisms.
