Effects of Polyethylene Terephthalate Microplastics on CA 15-3 Breast Cancer Marker, TNF-α and Breast Tissues of Chronically Exposed Female Albino Rats

Introduction: Breast cancer remains the leading cause of cancer-related deaths among women, with approximately 670,000 deaths globally. Emerging studies have linked exposure to various substances, including microplastics, to organ damage and cancer development. Polyethylene terephthalate (PET) is a common plastic polymer in Nigeria and a popular choice for beverage bottles, food packaging, and synthetic fibers. Over time, PET products can degrade into microplastics, contributing significantly to pollution and human toxicity. Aim: This study evaluated the effects of chronic exposure to PET-derived microplastics on CA 15-3 breast cancer marker, Tumor Necrosis Factor-alpha (TNF-α), and breast tissues in female albino rats. Methodology: Thirty-five female albino rats weighing 150–170g were used for the study. The rats were acclimatized for 14 days and randomly divided into five groups with 7 rats in each group. PET pellets were crushed to microplastics, dissolved in water and filtered before use. Group 2, 3, and 4 rats received 40mg/kg, 80mg/kg, and 120mg/kg PET-microplastics respectively, administered orally using gavage tubes for 90 days. Group 5 rats were given water exposed to sunlight between 10 am to 4pm daily in PET1 containers for 30 days, while Group 1 served as the negative control with standard food and water. After treatment, blood samples were collected to assess CA 15-3 and TNF-α using ELISA method, and breast tissues were also collected for histological examination. Statistical analysis was performed using GraphPad Prism (Version 9.0.0), with significance set at P≤0.05. Results: Results obtained showed that the mean levels of TNF-α in the rats exposed to PET were significantly higher than the levels in the control group at P<0.001. However, CA 15-3 levels showed no significant difference between PET-exposed rats and the control rats at P=0.077, indicating that CA 15-3 was not notably affected by PET exposure. Histological analysis revealed fibrocystic changes in the breast tissues of PET-exposed rats. Conclusion: These findings suggest that chronic PET microplastics exposure induced inflammatory responses and histological breast tissue alterations such as fibrocystic changes, which are significant indicators of tissue remodeling and potential disease risk. This highlights the potential health risks associated with prolonged PET exposure.