穿心草口山酮对激活细胞膜Na^+/H^+交换加重心脏缺血再灌注损伤的保护作用

Protective effects of xanthones on ischemia/reperfusion injury exaggerated by activation of Na^+/H^+ exchange system

目的 研究 3种穿心草口山酮 (xanthone ,Xan) :1,8 dihydroxy ,3 ,5 dimethoxyxanthone(Xan Ⅰ ) ;1 hydroxy ,3 ,5 dimethoxyxanthone(Xan Ⅱ ) ;1 hydroxy ,3 ,7,8 trithoxyxan thone(Xan Ⅲ )对激活细胞膜Na+/H+交换加重心脏缺血再灌注损伤的保护作用。方法 在离体大鼠等容收缩模型上 ,采用NH4 Cl负荷方法以激活细胞膜Na+/H+交换 ,观察在缺血前给予Xan对缺血再灌注损伤的影响。结果 Na+/H+交换组增加冠脉流出液中乳酸脱氢酶 (LDH)的含量 ,促进心肌组织脂质过氧化产物丙二醛 (MDA)的生成 ,加重心肌组织中Na+、Ca2 +超负荷和K+的丢失。浓度为 0 2 μmol·L-1的Xan可明显减轻上述作用 ,作用强度依次为Xan Ⅰ>Xan Ⅲ >Xan Ⅱ。结论 穿心草 3种Xan对激活细胞膜Na+/H+交换加重心脏缺血再灌注损伤有一定的保护作用。

AIM To study the protective effects of xanthones: 1,8 dihydroxy 3,5 dimethoxyxanthone(Xan Ⅰ); 1 hydroxy 3,5 dimethoxyxanthone(Xan Ⅱ);1 hydroxy 3,7,8 trithoxyxanthone(Xan Ⅲ) from Canscora lucidissima on ischemia reperfusion injury exaggerated by activation of Na +/H + exchange system. METHODS The perfused isovolumic contracting rat hearts were subjected to 20 mmol·L -1 NH 4Cl loading for promoting the Na +/H + exchange in the model of ischemic reperfusion injury and the protective effects being pretreated with Xans on the injury were examed. RESULTS Xans could relieve the effects: activation of Na +/H + exchange inhibited the recovery of ventricular function significantly, and exacerbated the myocardial injury as evidenced by increase in release of LDH, associated with the accumulation of intracellular Na +,Ca 2+ and the loss of intracelullar K +. CONCLUSION Xans has the protective effects on ischemic reperfusion injury exacerbated by activation of Na +/H + exchange system.