利用質譜儀為基礎的脂質體學探討全氟癸酸暴露後大鼠肝臟和血清脂質組成之變化

Abstract

全氟與多氟烷基物質（per- and polyfluoroalkyl substances, PFASs）是一類廣泛應用於工業製程及消費性產品中的人工合成化學物質，由於具有高度環境持久性、生物累積性及潛在健康危害，近年來受到廣泛關注。全氟癸酸（perfluorodecanoic acid, PFDA）屬於長碳鏈全氟羧酸類化合物，已有研究指出其可能造成脂質代謝異常及肝臟毒性。然而，PFDA對肝臟和血清中含磷酸膽鹼的脂質（phosphocholine-containing lipids, PC-CL），包括磷脂醯膽鹼（phosphatidylcholines, PCs）及鞘磷脂（sphingomyelins, SMs）之影響仍缺乏深入探討。因此，本研究利用質譜脂質體學方法，分析PFDA暴露後大鼠肝臟與血清中PC-CL的變化情形。 本研究以18隻雄性Sprague–Dawley大鼠為實驗動物，分別給予0、0.5及1 mg/kg/day PFDA經口灌餵21天。收集肝臟及血清樣本後，利用超高效液相層析串聯質譜儀進行PC-CL分析。經資料處理後，採用主成分分析及偏最小平方法判別分析評估各組脂質體差異，並利用Kruskal–Wallis檢定搭配假發現率校正篩選顯著變化脂質。 結果顯示，PFDA暴露造成肝臟與血清PC-CL組成顯著改變。其中，在肝臟和血清中，觀察到多數雙醯基磷脂醯膽鹼（diacyl-phosphatidylcholines, DPCs）隨暴露劑量增加而下降，而溶血磷脂醯膽鹼（lysophosphatidylcholines, LPCs）則呈現增加趨勢。進一步解析個別脂質分子的脂肪酸組成發現，多種含有多元不飽和脂肪酸（polyunsaturated fatty acids, PUFA）的PCs顯著下降，特別是含有花生四烯酸、二十碳五烯酸及二十二碳六烯酸的脂質分子。相反地，含18:3及20:3脂肪酸鏈的PCs則呈現增加趨勢。此外，部分縮醛磷脂膽鹼（plasmalogen-PC, P-PCs）及鞘磷脂亦出現選擇性變化。相較於血清，肝臟具有較多顯著改變的脂質種類，而血清則於多變量分析中呈現較佳的群組分離效果。 綜合而言，本研究利用質譜脂質體學方法揭示PFDA暴露後大鼠肝臟與血清中PC-CL的變化特徵。研究結果顯示，PFDA暴露與 PC 穩態、含多元不飽和脂肪酸磷脂及細胞膜磷脂組成的改變有關。本研究從分子層級完整描繪了 PFDA 所引起的脂質變化特徵。肝臟脂質體分析結果有助於了解 PFDA 所造成的肝臟脂質代謝擾動及其潛在肝毒性，而血清脂質體分析結果則顯示循環中的磷酸膽鹼類脂質具有作為 PFDA 暴露及其代謝效應生物監測候選指標的潛力。

Per- and polyfluoroalkyl substances (PFASs) are a group of synthetic chemicals that have attracted increasing concern because of their environmental persistence, bioaccumulation potential, and adverse health effects. Perfluorodecanoic acid (PFDA), a long-chain perfluoroalkyl carboxylic acid, has been associated with disturbances in lipid metabolism and hepatotoxicity. However, the effects of PFDA on phosphocholine-containing lipids (PC-CL), including phosphatidylcholines (PCs) and sphingomyelins (SMs), in the liver and serum remain poorly understood. The aim of this study was to characterize PFDA-induced alterations in PC-CL profiles in rat liver and serum using a mass spectrometry-based lipidomic approach. Eighteen male Sprague-Dawley rats were orally administered PFDA at doses of 0, 0.5 and 1 mg/kg/day for 21 days. Liver and serum were collected for PC-CL profiling using ultra-performance liquid chromatography coupled with tandem mass spectrometry. Following data processing, multivariate analyses, including principal component analysis and partial least squares discriminant analysis, were performed to evaluate lipid profile alterations among treatment groups. Univariate analysis was conducted using the Kruskal–Wallis test with false discovery rate correction to identify significantly altered lipid species. PFDA exposure induced significant alterations in PC-CL profiles in both liver and serum. Most diacyl-phosphatidylcholine species decreased in a dose-dependent manner, whereas lysophosphatidylcholine species exhibited increasing trends following PFDA exposure in the liver and serum. Structural characterization of individual lipid species further revealed selective reductions in polyunsaturated fatty acid (PUFA)-containing PCs, particularly arachidonic acid-, eicosapentaenoic acid-, and docosahexaenoic acid-containing species, accompanied by increases in 18:3- and 20:3-containing PCs. In addition, selective alterations in plasmalogen-PC and SM species were observed following PFDA exposure. A greater number of significantly altered lipid species were identified in the liver, whereas serum exhibited clearer separation among exposure groups in the multivariate analysis. In conclusion, this study characterized PFDA-induced alterations in PC-CL in the rat liver and serum using a mass spectrometry-based lipidomic approach. PFDA exposure was associated with changes in PC homeostasis, PUFA-containing phospholipids, and membrane phospholipid composition. These findings provide a comprehensive molecular-level characterization of PFDA-associated lipid alterations. The liver lipid profile provides insight into the metabolic perturbations associated with PFDA-induced hepatotoxicity, whereas the serum lipid profile highlights the potential of circulating PC-CL as candidates for biomonitoring PFDA exposure and its metabolic effects.