Screening and validation of differentially expressed serum proteins related to lipid metabolism in rats under subchronical arsenic exposure

Objective To screen and validate the differentially expressed serum proteins related to lipid metabolism in rats under subchronical arsenic exposure, and to provide serum protein biomarkers for lipid metabolism related diseases. Methods Sixty Wistar rats were randomly divided into four groups, and the dose of sodium arsenite in drinking water for each group was 0, 2, 10, and 50 mg/L, respectively, n = 15/group. The exposure lasted for 12 weeks. An isobaric tags for relative and absolute quantitation (iTRAQ)-based proteomic technique was used to identify the differential expressed proteins in serum between control and high-arsenic groups. Enzyme-linked immunosorbent assay (ELISA) method was applied to further validate differentially expressed proteins potentially related to lipid metabolism in the four groups. Results Totally 201 proteins were identified in rat serum, of which 12 were significantly changed which related to lipid metabolism including apolipoprotein A-Ⅱ (up-regulated, high-arsenic group/control = 1.40) and adiponectin (down-regulated, high-arsenic group/control = 0.75). Validation of ELISA experiment showed that the concentrations of serum apolipoprotein A-II in control, low-arsenic, middle-arsenic, and high-arsenic groups were (4.37 ± 1.08), (5.04 ± 0.37), (4.94 ± 0.84) and (4.65 ± 0.61) μg/L, respectively, and no significant difference was found among the four groups (F = 2.071, P > 0.05). The concentrations of serum adiponectin were (1.06 ± 0.43), (0.95 ± 0.42), (0.88 ± 0.28) and (0.54 ± 0.17) mg/L, and the value in high-arsenic group was significantly decreased as compared to that of control (P < 0.05). Conclusion This study has demonstrated that iTRAQ technology can be used in differential expression proteomics, and adiponectin may serve as a useful biomarker for damage to human health caused by arsenic poisoning. Key words: Arsenic exposure; Isobaric tags for relative and absolute quantitation; Serum; Biomarker; Apolipoprotein A-Ⅱ; Adiponectin