·糖尿病基础研究·

　　【摘要】 目的 观察棕榈酸(PA)对INS-1细胞胰岛素分泌功能及胰岛素信号分子基因表达的影响及抗氧化剂N-乙酰半胱氨酸(NAC)干预的效果，探讨氧化应激所起的作用及机制。 方法 INS-1细胞分为对照(NC)组、棕榈酸(PA)组及PA+NAC(PA+NAC)组，分别用0.2 mmol/L PA和/或0.2 mg/mL NAC进行干预，48 h后检测以下指标：⑴行胰岛素释放试验，检测INS-1细胞胰岛素分泌功能;⑵测定细胞内硝基酪氨酸含量：评价氧化应激水平;⑶实时荧光定量PCR反应，检测各组细胞胰岛素受体底物1(IRS-1)、胰岛素受体底物2(IRS-2)以及葡萄糖转运子2(Glut-2)基因表达的变化。 结果 (1)PA及NAC对INS-1细胞胰岛素分泌功能的影响：PA组ISI明显降低， PA+NAC组较PA组升高(1.16±0.11vs 0.84±0.12，P<0.05);(2)PA及NAC对INS-1细胞氧化应激水平的影响：PA干预细胞内硝基酪氨酸(NT)水平增加，NAC干预水平显著降低。(P<0.05);(3)与NC相比，PA组IRS-1,IRS-2以及Glut-2 mRNA表达均降低，分别为NC组的19.9%，29.8%，42.3% (P均<0.05)。PA+NAC组IRS-1,IRS-2以及Glut-2 mRNA表达分别比PA组增加22.4%，47.1%，80.0% (P均<0.05)。 结论 游离脂肪酸(FFA)长期刺激可使INS-1细胞GSIS功能下降，IRS-1,IRS-2以及Glut-2 mRNA表达降低，NAC抗氧化干预能改善INS-1细胞胰岛素信号传导，部分逆转脂毒性导致的β细胞分泌功能紊乱，其机制可能与NAC纠正氧化及抗氧化失衡有关。

　　【关键词】 棕榈酸;NAC;INS-1细胞;氧化应激

Effect of N-acetyl-l-cysteine on the expression of insulin signal gene of INS-1 cells intervened by free fatty acid and its mechanism WANG Bing, HOU Zhi-qiang, LI Hong-liang, et al. Department of Endocrinology, Meitan General Hospital, Beijing 100028, China

Corresponding author: YANG Wen-ying, Email: ywy-1010@yahoo.com.cn

　　【Abstract】 Objective To study the effect of palmitic acid (PA) on the insulin secretion of ins-1 cells and expression of insulin signal transduction molecules and the effect of intervention with N-acetyl-l-cysteine (NAC) for discussing the functions and mechanism of oxidative stress. Methods The INS-1 cells were divided into NC group, PA group, and PA+NAC group, which were treated with 0.2 mmol/L PA and/or 0.2 mg/mL NAC respectively. After 48 hours, ① the insulin release test was done to determine the insulin secretion in INS-1 cells; ② the content of nitrotyrosine in cells was measured to evaluate the oxidative stress level; and ③ the changes in gene expression of IRS-1,IRS-2, and Glut-2 were detected with real-time PCR. Results ① the effect of PA and NAC on the insulin secretion in INS-1 cells: ISI was significantly lowered in the PA group, while it was higher in the PA+NAC group than in the PA group (1.16±0.11vs 0.84±0.12, P<0.05); ② the effect of PA and NAC on the oxidative stress level of INS-1 cells: the content of nitrotyrosine (NT) treated with PA was increased, while treated with NAC decreased (P<0.05); and ③ compared with the normal control group, the expression of IRS-1,IRS-2, and Glut-2 mRNA in the PA group was all reduced, only being 19.9%, 29.8%, and 42.3% respectively of the normal control group (P all<0.05); compared with the PA+NAC group, those were increased, being 22.4%, 47.1%, and 80.0% respectively higher than in the PA+NAC group (P all<0.05). Conclusion Free fatty acid may weaken the GSIS function of INS-1 cells and lower the IRS-1, IRS-2, and Glut-2 mRNA expression. The intervention with NAC for anti-oxidation may improve the insulin transduction signals of INS-1 cells and partially correct the secretion disorders of pancreatic islet β cells caused by lipid toxicity. The mechanism may be associated with NAC correcting the imbalance between the oxidation and anti- oxidation.

　　【Key words】Free fatty acid; N-acetyl-l-cysteine (NAC); INS-1 cells; Oxidative stress