白细胞介素-2降低缺氧/复氧心肌细胞对细胞内钙的处理能力

INTERLEUKIN-2 REDUCES CALCIUM HANDLING CAPACITY OF RAT VENTRICULAR MYOCYTES DURING ANOXIA/REOXYGENATION

目的 :研究在正常和缺氧 /复氧过程中白细胞介素 2 (IL 2 )对心肌细胞收缩和细胞内钙的处理能力的影响。方法 :采用酶解分离大鼠心室肌细胞化学缺氧模型 ,用视频跟踪系统和细胞内双波长钙荧光系统检测单个心肌细胞收缩和细胞内钙的变化。结果 :①缺氧过程中 ,心肌细胞收缩被抑制 ,钙瞬变幅度降低、静息钙水平增高 ,咖啡因诱导的钙释放减少 ,但对细胞膜L -型钙通道活性无明显影响 ;复氧期间 ,各指标不能恢复到对照水平。②IL 2 (2× 10 5U/L)抑制心肌细胞收缩 ,使钙瞬变幅度降低、静息钙水平增高 ,使咖啡因诱导的钙释放减少。③在缺氧期间加入IL 2 (2× 10 5U/L)后 ,复氧期间各参数回复均减慢。结论 :缺氧时同时存在IL 2 ,可加剧复氧时心肌细胞收缩功能和钙处理能力的降低 ,这可能与心肌细胞肌浆网内贮钙释放减少有关。

Aim: To investigate the effect of interleukin-2(IL-2) on the cell contractility and calcium handling in cardiomyocytes during normoxia or anoxia/reoxygenation. Methods: Chemical anoxia introduced by Krebs-Henseleit(K-H) solution containing 10 -3 mol/L sodium dithionite was used in the enzymatically isolated rat ventricular myocytes. The video-tracking system and spectrofluorometric method were employed to verify the cell contraction and calcium handling of the single myocyte. Results: During anoxia, the cell contraction, amplitude of calcium transient induced by electrical stimulation and Ca 2+ release induced by caffeine were depressed while resting calcium level was elevated, but the activity of the L-type calcium channels were not changed. All the parameters could not return to the pre-anoxia level during reoxygenation. IL-2 at 2×105 U/L administrated during anoxia aggravated the effect of rexoxygenation on cell contraction and the calcium handling. Conclusion:Coexistence of IL-2 during anoxia aggravated the effect of reoxygenation on the cell contraction and calcium handling in the isolated rat ventricular myocytes, in which the reduced calcium release from sarcoplasmic reticulum was involved.