目的 研究新型褪黑素受体激动剂Neu-P11对心肌细胞缺氧/复氧损伤的作用及分子机制.方法 实验分为对照组、缺氧/复氧模型组(H/R组)、H/R+Neu-P11组、H/R+Compound C组、H/R+Neu-P11+Compound C组.构建H9c2心肌细胞缺氧/复氧模型,检测各组心肌细胞凋亡情况,细胞培养液中乳酸脱氢酶(LDH)、肌酸激酶(CK)、SOD活性及MDA含量及心肌细胞AMPK的活性.结果 与缺氧/复氧组细胞相比,Neu-P11预处理组细胞凋亡率明显减少,CK、LDH、MDA含量明显下降,SOD活性增加,心肌细胞AMPK活性明显增高,而AMPK特异性抑制剂Compound C可以阻断Neu-P11的保护作用.结论 Neu-P11能够减轻心肌细胞缺氧/复氧损伤,这一保护作用与激活AMPK有关.

目的 探讨褪黑素受体激动剂Neu-P11对胰岛素抵抗3T3-L1脂肪细胞IRS-1和GLUT-4表达的影响.方法 用高糖高胰岛素作用3T3-L1脂肪细胞24 h,建立胰岛素抵抗细胞模型.分别采用褪黑素、Neu-P11、褪黑素+luzin-dole(褪黑素受体拮抗剂)和Neu-P11+ luzindole处理细胞,并以未加药细胞作为对照.用葡萄糖氧化酶法检测培养液中的糖含量并计算糖消耗量,用蛋白质印迹分析检测细胞内IRS-1、GLUT-4蛋白表达变化.结果 胰岛素抵抗细胞用褪黑素和Neu-P11处理后,糖消耗量较未加药对照组升高(P＜0.05),GLUT-4、IRS-1的蛋白表达也增高(P＜0.05)；褪黑素和Neu-P11分别与luzindole联合作用于细胞后,细胞的上述蛋白表达较单用褪黑素组和单用Neu-P11组降低(P＜0.05),而与未加药对照组相比差异无统计学意义.结论 褪黑素受体激动剂Neu-P11可提高胰岛素抵抗脂肪细胞的胰岛素敏感性,增加糖消耗量,这种作用可能与上调IRS-1、GLUT-4蛋白的表达有关.

目的探讨脂肪组织甘油三酯酶（adipose triglyceridelipase,ATGL）及激素敏感性脂肪酶（hormone-sensitive lipase,HSL）在褪黑素非选择性受体激动剂Neu-p11改善高糖高胰岛素（high glucose and insulin,HGI）诱导的3T3-L1脂肪细胞胰岛素抵抗（insulin resistance,IR）中的作用及机制。方法培养3T3-L1脂肪细胞,HGI诱导IR模型。以葡萄糖消耗量及细胞内甘油三酯（triglyceride,TG）定量测定作为检测指标,Western blot检测蛋白水平的表达情况。结果 HGI孵育减少脂肪细胞葡萄糖摄取,促进细胞内TG积聚,同时伴有ATGL及HSL的蛋白表达下调。Neu-p11干预逆转了HGI对脂肪细胞的作用效应,而MT2竞争性拮抗剂luzindole却拮抗了Neu-p11的上述效应。结论 Neu-p11以MT2受体依赖性方式抑制IR脂肪细胞TG沉积,可能与其上调AT-GL、HSL蛋白的表达,促进TG水解相关。

Piromelatine, a novel investigational multimodal sleep medicine, is developed for the treatment of patients with primary and co-morbid insomnia. Piromelatine has been shown to inhibit weight gain and improve insulin sensitivity in high-fat/high-sucrose-fed (HFHS) rats. Considering that piromelatine has also been implicated in lowering of triglyceride levels in HFHS rats, this work elucidated whether this effect involves in the regulation of adipose triglyceride lipase (ATGL) and hormone-sensitive lipase (HSL) in triglyceride (TG) metabolism. In this study, we investigated the effects of piromelatine and MT2 receptors inhibition on TG content, insulin-stimulated glucose uptake, and the expressions of ATGL and HSL in 3T3-L1 adipocytes preincubated in high glucose and high insulin (HGI) conditions. Our results showed that culturing 3T3-L1 adipocytes under HGI conditions increased triglyceride accumulation with concomitant decrease of ATGL and HSL expression, inducing insulin resistance in 3T3-L1 adipocytes. We also found that triglyceride accumulation was significantly inhibited and the levels of ATGL/HSL increased after melatonin or piromelatine treatment. The effects of melatonin/piromelatine (10 nM) were counteracted by pretreatment with the relatively selective MT2 receptor antagonist luzindole (100 nM). In this study, our data demonstrate that piromelatine reverses high glucose and high insulin-induced triglyceride accumulation in 3T3-L1 adipocytes, possibly through up-regulating of ATGL and HSL expression via a melatonin-dependent manner.

Adiponectin is a protein secreted exclusively by white adipose tissue and is abundantly present in human plasma.It has essential biological effects,and its protective effects on arteral wall have become a research hotspot.The globular domain of adiponectin is considered to be bioactive.It is a new target for studying the protective mechanism for vascular wall,which may have great significance in the preventive and therapeutic strategies of atherosclerosis.

LPL (lipoprotein lipase) is a rate-limiting enzyme involved in the hydrolysis of triglycerides. Previous studies have shown that microRNA (miR)-467b regulates hepatic LPL expression and plays a role in the progression of steatosis or abnormal lipid retention in obese mice. Macrophage-derived LPL has been shown to promote atherosclerosis. However, if miR-476b influences macrophage LPL expression and the subsequent effects are unknown. Here, we utilized oxLDL-treatment RAW 264.7 macrophages that were transfected with miR-467b mimics or inhibitors to investigate the potential roles of macrophage miR-476b. We found that miR-467b significantly decreased lipid accumulation and IL-6, IL-1β, TNF-α and MCP-1 secretions. Furthermore, our studies suggested an additional explanation for the regulatory mechanism of miR-467b on its functional target, LPL in RAW 264.7 macrophages. Thus, our findings indicate that miR-467b may regulate lipid accumulation and proinflammatory cytokine secretion in oxLDL-stimulated RAW 264.7 macrophages by targeting the LPL gene.