In vivo and in vitro effects of chronical exposure to nonylphenol on lipid metabolism

Abstract

Background: The incidence of obesity has soared over the last several decades. There is mounting evidence suggesting that the increased presence of environmental endocrine disruptors (EEDs), including nonylphenol (NP), plays an important role in the incidence of lipid metabolism disorders. The aim of this work was to determine whether chronical exposure to NP could induce obesity and lipid metabolism disorders, both in vivo in Sprague-Dawley rats, and in vitro in 3T3-L1 preadipocytes. Forty rats (n = 10 per group) were gavaged with NP in corn oil at dose levels of 0.02 μg/kg/day (low dose, L), 0.2 μg/kg/day (middle dose, M), and 2.00 μg/kg/day (high dose, H) or corn oil alone (vehicle control, C) for 180 days. In vitro study, 3T3-L1 preadipocytes were exposed to NP at concentrations of 0, 40 pM, 40 nM, or 40 μM for 12 days. Results: In vivo, the fat weight (F = 103.605, P < 0.001) and fat coefficient (F = 169.807, P < 0.001) of NP-exposed rats were higher than those of control group rats. The serum levels of TC (F = 3.798, P < 0.05), LDL-C (F= 4.946,P < 0.05), and TG (F = 14.117,P < 0.05) in the H group were higher than those in the control group. Protein concentrations of CEBPα (F = 189.104, P < 0.001), FAS (F = 51.011, P < 0.001), PPARγ (F = 114.306,P < 0.001), and SREBP1 (F = 30.432,P < 0.001) in serum in the NP group were higher than those in the control group. The concentration of NP in adipose tissues of rats increased with an increase in NP exposure dose in a dose-response manner (F = 561.353,P < 0.001). The numbers of adipocytes in the M and H groups decreased, and the volume of a single cell increased with cells' membranes ruptured. With the increase in NP exposure dose, the number of adipocytes per microscope decreased gradually (F = 85.873, P < 0.001). The expression levels of PPARγ (F = 169.936, P < 0.001) and FAS (F = 295.249, P < 0.001) proteins in the H group were higher than those in the control group. CEBPα (F = 101.086, P < 0.001) mRNA expression was up-regulated in the M and H groups; and FAS (F = 439.600, P < 0.001), PPARγ (F = 10.540, P < 0.001), and SREBP1 (F = 123.499, P < 0.001) mRNA expression in NP-exposed groups were significantly higher than those in the control group. In vitro, compared with the control group, the Oil Red Staining of adipocytes in the NP groups was darker, the fat cells were more densely distributed, and some of them fused into large lipid droplets. Expressions of CEBPα (F = 539.103, P < 0.001), FAS (F = 715.740, P < 0.001), PPARγ(F = 114.783, P < 0.001), and SREBP1 (F = 139.600, P < 0.001) proteins in 3T3-L1 preadipocytes were higher in group exposed to 40 μM NP than those in the control group. Conclusions: The results of this in vivo and in vitro experiment were consistent, and both have demonstrated that NP exposure interfered with the expression of proteins and/or mRNAs of lipid metabolism-related regulators (CEBPα, FAS, SREBP1, PPARγ), promoted the proliferation and differentiation of adipocytes and intracellular accumulation of lipids, and eventually lead to blo...

Lipid metabolism analysis providing insights into nonylphenol multi-toxicity mechanism

“…In mammals, the transcriptional levels of adipose related target proteins (including factor-related apoptosis, CEBPα, PPARγ) were also upregulated in NP-exposed rats. 45 Interaction with other phenolic compounds also contributes to the disruption of lipid-related transcriptional processes. Bisphenol A, NP, and Octylphenol share similar modes of action involving the phenyl hydroxyl group, which has common effects on lipid-related pathways, like de novo lipogenesis processes.…”

“… 14 Furthermore, NP fosters the proliferation and differentiation of adipocytes, contributing to abnormal weight gain. 15 The augmentation of storage lipids may additionally expedite the bioaccumulation of NP, creating a positive feedback loop between NP accumulation and fat storage. While the physiological impacts of NP on organisms are broadly understood, the connection between NP-adjusted lipid metabolism and its underlying toxic effects remains undisclosed.…”

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Whitlockite nanoparticle-coated hydroxyapatite granules for bone regeneration in defect of rat calvaria

“…The expression levels of the lipid metabolism-related proteins were quanti ed with the Western blot assay as described elsewhere [39,40]. The total proteins were extracted from MG63 cells using Pro-Prep Protein Extraction Solution (iNtRON Biotechnology, Seongnam, Korea) and quanti ed with SMARTTM BCA Protein Assay Kit (Thermo Scienti c Inc.…”