CAJ | 학술논문

目的：探讨褪黑素（ MT）对亚油酸（ LA）引起HepG2细胞胰岛素信号缺陷的修复作用及其机制。方法将培养的HepG2细胞分为对照组（ BSA组）、亚油酸组（ LA组）、亚油酸＋褪黑素组（ LA＋MT组）、亚油酸＋维生素C组（ LA＋VitC组）。 BSA组予以10％牛血清白蛋白处理24 h；LA组予以0．5 mmol? L－1亚油酸处理24 h， LA＋MT组予以10μmol? L－1褪黑素和0．5 mmol? L－1亚油酸处理24 h；LA＋VitC组予以1 mmol? L－1维生素C和0．5 mmol? L－1亚油酸处理24 h。用荧光比色法测定各组细胞胞内氧自由基水平，用Western印迹法检测胰岛素刺激后胞内胰岛素信号蛋白磷酸化水平，包括蛋白激酶B、叉头转录因子以及c－Jun氨基末端激酶。结果 LA组的氧自由基含量明显高于BSA组（P＜0．05）；LA＋MT组的氧自由基含量明显低于LA组（P＜0．05）；LA＋MT组与BSA组相比，氧自由基含量差异无统计学意义（ P＞0．05）。 LA＋VitC组与LA组相比，氧自由基的含量减少，但仍高于 LA＋MT 组，差异有统计学意义（ P＜0．05）。LA组与BSA组相比，蛋白激酶B、叉头转录因子磷酸化水平减少，而c－Jun氨基末端激酶磷酸化水平升高；LA＋MT组与LA组相比，蛋白激酶B、叉头转录因子磷酸化水平显著升高， c－Jun氨基末端激酶磷酸化水平明显降低，组间比较差异有统计学意义（ P＜0．05）。结论亚油酸可导致细胞内氧自由基增加，褪黑素能够清除亚油酸产生的过量氧自由基，减少c－Jun氨基末端激酶的活化，修复胰岛素下游信号损伤。
목적：탐토퇴흑소（ MT）대아유산（ LA）인기HepG2세포이도소신호결함적수복작용급기궤제。방법장배양적HepG2세포분위대조조（ BSA조）、아유산조（ LA조）、아유산＋퇴흑소조（ LA＋MT조）、아유산＋유생소C조（ LA＋VitC조）。 BSA조여이10％우혈청백단백처리24 h；LA조여이0．5 mmol? L－1아유산처리24 h， LA＋MT조여이10μmol? L－1퇴흑소화0．5 mmol? L－1아유산처리24 h；LA＋VitC조여이1 mmol? L－1유생소C화0．5 mmol? L－1아유산처리24 h。용형광비색법측정각조세포포내양자유기수평，용Western인적법검측이도소자격후포내이도소신호단백린산화수평，포괄단백격매B、차두전록인자이급c－Jun안기말단격매。결과 LA조적양자유기함량명현고우BSA조（P＜0．05）；LA＋MT조적양자유기함량명현저우LA조（P＜0．05）；LA＋MT조여BSA조상비，양자유기함량차이무통계학의의（ P＞0．05）。 LA＋VitC조여LA조상비，양자유기적함량감소，단잉고우 LA＋MT 조，차이유통계학의의（ P＜0．05）。LA조여BSA조상비，단백격매B、차두전록인자린산화수평감소，이c－Jun안기말단격매린산화수평승고；LA＋MT조여LA조상비，단백격매B、차두전록인자린산화수평현저승고， c－Jun안기말단격매린산화수평명현강저，조간비교차이유통계학의의（ P＜0．05）。결론아유산가도치세포내양자유기증가，퇴흑소능구청제아유산산생적과량양자유기，감소c－Jun안기말단격매적활화，수복이도소하유신호손상。
Objective To study the effects of melatonin ( MT) on insulin signaling transduction defect induced by linoleic acid ( LA) and the un-derlying mechanism.Methods HepG2 cells were divided into BSA group, LA group, LA+MT group and LA+VitC group cultured with va-rious agent concentrations of 10% BSA, or 0.5 mmol? L-1 LA, or 10μmol? L-1 MT plus 0.5 mmol? L-1 LA, and 1 mmol? L-1 Vitamin C plus 0.5 mmol? L-1 LA, respectively for 24h.The level of intracellular ROS was measured by fluorometry.Phosphorylation levels of protein ki-nase B ( PKB) , Forkhead box O1 ( FoxO1 ) , and c-Jun N-terminal kinase ( JNK) were determined in total cell lysates by Western-blotting with insulin stimulation.Results ROS level increased significantly in LA group compared with that in BSA group, and was significantly higher compared with that in LA +MT group ( P <0.05 ) . There was no significant difference in ROS level between LA+MT group and BSA group.Compared with LA group, the production of ROS in LA+VitC group decreased, but significantly higher than that in LA+MT group ( P<0.05 ) .Compared with BSA group, the phosphorylation levels of both PKB and FoxO1 in LA group significantly decreased, whereas, phospho-rylation level of JNK increased significantly ( P<0.05 ) .Copared with LA group, phosphorylation levels of PKB and FoxO1 in LA +MT group increased significantly, whereas, phosphorylation level of JNK significantly decreased (P<0.05).Conclusion LA causes the increased production of ROS in HepG2 cells.MT treatment can clear the excessive LA-induced ROS, reduce the activation of c-Jun amino terminal kinase and repair the impaired insulin downstream signal.