Dioxins are a group of highly toxic environmental persistent organic pollutants, which are lipophilic in nature. 2, 3, 7, 8- tetrachlorodibenzo-p-dioxin (TCDD) is the most toxic representative of this class. TCDD causes several human health effects like endocrine disruption, carcinogenesis and reproductive toxicity mediated by aryl-hydrocarbon receptor. Current detection methods of dioxins like gas chromatography-mass spectrometry, liquid chromatography-mass spectrometry etc. are costly and time consuming. Therefore, the present study aims to develop a relatively faster and cheaper technique called reverse transcription-loop mediated isothermal amplification (RT-LAMP) assay to detect dioxins. Cultured granulosa cells used as a model system were treated with different doses (5, 10 and 15 pg/mL) of aryl hydrocarbon receptor (AhR)responsive xenobiotic, TCDD, in accordance with maximum residue limit values. Cells were treated for 6, 12 and 24 h, respectively to study the gene expression of TCDD receptor called AhR and AhR responsive genes, CYP1A1 and CYP1B1, in a dose and time dependent manner. All targeted genes expression significantly increased after 6 and 12 h by 1.3-8 folds. For the development of RT-LAMP assay, CYP1A1 gene was used with 6 h TCDD treatment. RT-LAMP assay was standardized with optimal color change at 30 min using 50 ng of cellular RNA. In all the cases, we could distinguish RT-LAMP-positive condition from one sample to another sample due to intensity of color. The method was also validated by spectrometric method. In conclusion, the developed method will be used to screen AhR receptor responsive xenobiotics by observing the color change in RT-LAMP assay like dioxin used in the present study.
Keywords: AhR; CYP1A1; RT-LAMP; TCDD; Xenobiotics.