红花黄素对氧自由基所致的心肌细胞电生理异常的保护作用

背景氧自由基诱导的功能异常可能使心脏、肝脏、肾脏及脑等组织缺血性疾病的主要致病因素,对损伤有保护作用的药物研究成为当前的热点.目的研究红花黄素(Saffloweryellow pigment,SYP)对氧自由基引起的豚鼠单个心室肌细胞损伤的保护作用.设计非随机对照的实验研究.地点、材料和干预本实验在哈尔滨医科大学药学院药理教研室完成.实验选用豚鼠30只,性别不限.以处置前单个心室肌细胞为正常对照,预先应用红花黄素(3.3μg/L)后,给予单个豚鼠心室肌细胞外源性氧自由基(1mmol/L的H2O2).主要观察指标采用全细胞膜片钳技术,观察单个豚鼠心室肌细胞动作电位时程(actionpotential duration APD)和L-型钙电流、内向整流钾电流.结果1 nnnol/L的H2O2导致豚鼠心室肌细胞损伤,表现为动作电位时程缩短,APD50和APD90分别由正常对照组的(331.2±31.9)ms和(380.8±28.2)ms缩短至(169.5±76.0)ms和(238.4±21.3)ms(n=8,t=3.834,P＜0.01),红花黄素(3.3μg/L)能明显改善H2O2诱发的动作电位时程缩短;同时氧自由基H2O2抑制L-型钙电流,+10mV时,L-型钙电流峰值由对照的(-1023.45±74.34)pA减少到(-275.21±38.67)pA(n=6,P＜0.001);H2O2(1mmol/L)也明显抑制内向整流钾电流(IK1),指令电位为-120 mV时,IK1由对照组的(-2133.5±570.4)pA降低到(-567.0±218.0)pA.预先应用红花黄素10 min后,外源性氧自由基引起单个豚鼠心室肌细胞L-型钙电流的抑制作用得以改善,但不能改变H2O2对Ik1的抑制作用.结论预先应用红花黄素对H2O2损伤有一定的拮抗作用,说明其能够清除氧自由基,为临床应用治疗缺血性心脏病和康复措施的介入提供理论依据.

Effect of safflower yellow pigment on abnormal electrophysiology of cardiac myocytes induced by oxygen-derived free radical

BACKGROUND: Dysfunction induced by free radicals is the major cause of ischemic diseases of the heart, bowel, liver, kidney, and brain. It is a hot topic to develop drugs which can prevent cells from damages caused by free radicals.OBJECTIVE: To study the protective effect of safflower yellow pigment (SYP) on the electrophysiological abnormality induced by oxygen derived free radical in single guinea pig ventricular myocytes.DESIGN: Non-randomized case control study.SETTINGS, PARTICIPANTS and INTERVENTIONS: This study was completed in Department of Pharmacology of Harbin Medical University. A total of 30 guinea pigs were selected without considering gender. The single ventricle myocyte before intervention was used as normal control. Exogenous oxygen-derived free radicals( 1 mmol/L of H2O2) were given to single ventricle myocyte of guinea pig when SYP(3.3 μg/L) was given in advance.MAIN OUTCOME MEASURE: Whole-cell patch clamp techniques wereused to record action potential dration (APD), L-type calcium current(ICa)and inward rectifier potassium current(Ik1).RESULTS: H2O2(1 mmol/L) led to the damage of ventricle myocytes of Guinea pig which was presented by decrease of action potential duration. The APD50 and APD90 were shortened from (331.2±31.9) ms and(380.8±28.2) ms to(169.5±76.0) ms and(238.4±21.3) ms(n=8, t= 3. 834, P＜0.01)respectively. Pretreatment with SYP(3.3 μg/L ) could markedly attenuate the injury effect of H2O2 on APD; H2O2 significantly inhibited L-type calcium current (ICa) from(-1 023.45±74.34) pA to ( - 275.21 ± 38.67) pA(n = 6, P＜ 0.001) at the test potential 10 mV. H2O2also inhibited inward rectifier potassium current of normal group from (-2 133.5±570.4) pA to(-567.0±218.0) pA at the test potential of - 120 mV. Although the inhibitory effects on L-type Ica of ventricle myocytes for ten minutes, which caused by exogenous oxygen-derived free redicals could be improved, the effect of H2O2 on IK1 could not be changed.CONCLUSION: SYP can antagonise the damage induced by free radical. It suggests that free radical can be cleared away by SYP. This study provides the mechanical basis for the treatment of ischemic heart disease and invention of rehabilitation.