Evaluation of Lipid and Cardiovascular Parameters in Albino Rats Exposed to Polyethelene Teraphthalate

Cardiovascular disease (CVD is the leading non-communicable cause of death accounting for approximately 30% of all deaths worldwide. Recently, different natural and chemical substances including microplastics which are plastic particles with a diameter less than 5 mm have been implicated in causing damage to organs of the body including cardiovascular health and diabetes. Aim: This study was conducted to evaluate the effects of chronic exposure to microplastics in drinking water on some biochemical parameters in albino rats. Methodology: A total of Thirty-seven (37) albino rats weighing 130-150g were used for this study. Polyethylene terephthalate (PET) microplastics pellets were obtained, crushed, dissolved in water and filtered before use. Pilot study was carried out to determine the LD50 of PET microplastic administered orally using the Lorke’s method of pilot toxicity testing. After allowing fourteen (14) days for acclimatization, the rats were randomly assigned into 5 groups with 5 rats in each group. The PET treatment was administered orally for 3 months. 40mg/kg, 80mg/kg and 120mg/kg PET microplastic were given to animals in groups 2, 3, and 4 respectively. Group 5 received water exposed to sunlight between 8am to 4pm daily for 30 days in PET containers while group 1 was normal control receiving food and water only. After the duration of treatments, blood samples were collected for analysis of total cholesterol (TC), triglycerides (TG), high density lipoprotein cholesterol (HDL) and glycated haemoglobin (HBA1c) using colorimetric methods while the LDL cholesterol levels were calculated using the Friedwald’s equation. Atherogenic indices such as Castelli Risk Index I (CRI-I), Castelli Risk Index II (CRI-II) and Atherogenic Coefficient (AC) were also calculated from the lipid profile values. Fasting blood glucose (FBG) were analysed using glucose oxidase method while Cardiac troponin I (cTn-I) and TNF a were evaluated using ELISA method. Statistical analysis was computed using GraphPad Prism Software Version 9.0.0 (121), San Diego, CA. Data obtained from this study were presented as mean ± SD. Statistical comparison between groups were done using one-way ANOVA, while Tukeys multiple comparison were used to obtain specific significant differences among the various groups. Differences were considered significant at P<0.05. Results: Results obtained revealed the LD50 of PET administered orally to be 122.27mg/kg. There was a significant increase in levels of cardiac troponin I, Tumor Necrosis Factor Alpha, total cholesterol, LDL cholesterol, CRI-I, CRI-II, AC, fasting blood glucose and glycated haemoglobin in the PET treated groups compared to the control at (p<0.05). Similarly, the mean cardiac troponin I and TNF a, levels in the group treated with bottled water exposed to sunlight were significantly higher than in the control group but significantly lower than in the PET-treated groups at p<0.05. Conclusions: The findings from this study demonstrate that chronic exposure to PET microplastics induces significant alterations in these biochemical biomarkers in albino rats suggesting that PET microplastics may contribute to inflammation, cardiovascular disorders, and impaired glucose metabolism, which may increase the risk of insulin resistance and diabetes, thus, emphasizing the potential health risks associated with PET microplastic ingestion.