左旋精氨酸与维生素B6对低密度脂蛋白抑制兔胸主动脉内皮舒张功能的影响

目的观察正常人的低密度脂蛋白(native low density lipoprotein,nLDL),人工氧化的低密度脂蛋白(oxidized lowdensity lipoprotein,ox-LDL)及非胰岛素依赖型糖尿病(Non-insulin dependent diabetes mellitus,MDDM)患者的低密度脂蛋白(diabetic low density lipoprotein,dLDL)对兔胸主动脉环内皮的损伤作用及左旋精氨酸(L-arginine,L-Arg),维生素B6(pyridoxine,VB6)的拮抗效应.方法采用离体动脉环灌流的方法,观察兔胸主动脉环对乙酰胆碱(acetycholine,Ach),钙离子载体A23187的舒张反应.结果3种LDL均抑制动脉环对Ach及A23187的舒张,损伤强度为ox-LDL＞dLDL＞nLDL,并具有浓度依赖性;L-Arg、VB6能明显拮抗LDL的抑制作用,但并不能完全逆转.以SOD作为保护药对照,250 U/ml的浓度能够显著抑制dLDL对内皮的损伤.结论3种低密度脂蛋白主要可能通过降低NO生物活性损伤内皮,L-Arg、VB6具有内皮保护作用.

Effect of LDL on the Endothelium of Rabbit Aortic Rings by L-arginine and Pyridoxine

Objective: To observe the effect of the LDL from healthy people and NIDDM patients and oxidized LDL on the rabbit aortic endothelial dysfunction, and the protective effect of L-arginine(L-Arg) and Pyridoxine (VB6) . Methods: By organ-chamber technique, the rabbit aortic relaxant responses induced by Ach and A23187 in vitro were observed. Results: The inhibitory effect of LDL on aortic rings to the vasodilatory responses induced by Ach or A23187 was concentration-dependent and the intensity rank was ox-LDL > dLDL > nLDL; Both L-Arg and VB6 were able to reverse the effect of LDL partially. As a known antioxidant, SOD(250 U/ml) could significantly inhibit the effect of LDL. Conclusion: LDL inhibit the endothelium-dependent vasodilation by reducing the activity of NO; L-Arg and VB6 are able to protect endothelium from being damaged by LDL.