The Expression Of AhR And Metabolic Enzymes In Liver Of Rats Exposed To Organic Extracts From Drinking Water

Objective: Using the previous animal model of liver damage in rats which exposed to organic extracts from drinking water, to observe Ah R and metabolic enzymes’ s expression. Exploring the organic extracts from drinking water’s role of abnormal liver bioconversion in liver damage. Methods: Extracting the organic compounds from the pipeline water from July to September(wet season) in 2012. 50 SD rats were randomly divided into blank group, solvent control group(with corn oil) and 3 exposed to organic extracts from drinking water groups with 10 rats in each group(half male and female). Exposed groups were administered respectivively with organic pollutants extracted from 5, 20, 80 liter pipeline water per kilogram body weight per day. The exposure time lasted 12 weeks. To prepare rats serum, spectrophotometry was measuring the enzyme activities of ALT, AST, CHE and the content of TP, ALB. Total RNA was extracted from liver tissue, real-time quantitative PCR was taken to measure m RNA expression level of Ah R, HSP90, ARNT, CYP1A2, CYP2E1, GSTA1. Total protein was extracted from liver tissue, western blot was taken to detect protein expression level of Ah R, HSP90, ARNT, CYP1A2, CYP2E1, GSTA1. To prepare liver homogenate, spectrophotometry was measuring the enzyme activities of GSTs. To prepare liver microsome, fluorescence spectrophotometry and chromatometry were detected to evaluate the activities of CYP1A2 and CYP2E1 separately. Correlation was analyzed between Ah R, liver metabolic enzymes and liver damage by spearman. Results:(1) With the rise of exposing dose, the enzyme activities of CHE in middle and high dose group both obviously increased significantly, the ALT and AST only in high dose group increased(P<0.05). Compared with the control group, the content of TP and ALB obviously reduced inhigh dose, a statistical difference exited(P<0.05).(2)Compared with the control group, the m RNA and protein expression level of HSP90 in low, middle and high dose groups obviously increased, the m RNA and protein expression level of Ah R, ARNT increased only in middle and high groups(P<0.05).(3)Compared with the control group, the m RNA and protein expression of CYP1A2 and GSTA1 in middle and high dose group both increased significantly, the CYP2E1 m RNA expression only in high dose group increased(P<0.05). With the rise of exposing dose, the m RNA and protein expression level of GSTA1 in high dose group significantly reduced compared with middle dose, had a statistically significant difference(P<0.05). The enzyme activities of CYP1A2 and GSTs in middle and high dose was obviously increased, and CYP2E1 in high dose was increased(P<0.05). While compared with the middle dose group, the activities of GSTs in high dose group significantly reduced(P<0.05).(4)The CYP1A2, GSTs enzyme activities with Ah R protein level had shown positive correlation(P<0.05). The serum CHE level with Ah R protein level and CYP1A2, CYP2E1, GSTs enzyme activities had shown positive correlation(P<0.05). Conclusions:(1)Under the condition of this experiment, exposing to high level organic extracts from drinking water can activate Ah R which can regulate the transcription and translation expression of HSP90 and ARNT ligands.(2)The abnormal regulate of Ah R pathway can increase the m RNA and protein expression of downstream CYP1A2 and GSTA1 metabolic enzymes genes, thus induce rise of the enzyme activities.(3)With the abnormal rise of metabolic enzyme activities, it can induce free radical and toxicity intermediate to rise while metabolized organic extracts from drinking water, thus to destroy cellular structure, result liver damage.