The cardioprotective effect and mechanism of lumbrokinase
Sun, H-li.; Jiao, J-dong.; Pan, Z-wei.; Dong, D-li.; Yang, B-feng.
Yao Xue Xue Bao 41(3): 247-251
2006
ISSN/ISBN: 0513-4870 PMID: 16758997 Document Number: 595899
Aim To investigate the protective effect of lumbrokinase against myocardial ischemia and to further explore its underlying mechanisms. Methods The effect of lumbrokinase on myocardial ischemia was observed by a model of acute myocardial infarction due to permanent ligation of the left anterior descending coronary artery in rats. Patch-clamp technique and laser scanning confocal microscopy were utilized to study the action of lumbrokinase on L-type calcium current (ICa-L) and intracellular calcium concentration ([Ca2+](i)). Results Lumbrokinase decreased the infarct size of myocardium in a dose-dependent manner. The inhibitory rate of lumbrokinase at the dose of 20, 40 and 80 mg . kg(-1) was 7.7%, 34.6% and 46.2%, respectively. The electrophysiological studies displayed that, at + 10 mV, the was markedly reduced from ( -14.42 +/- 1.53) pA/pF to (-11.33 +/- 1.40) pA/pF decreased by 21.4%, P < 0.01) and (-9.92 +/- 1.31) pA/pF (decreased by 36.5%, P < 0.01) by lumbrokinase (10 and 50 mu mol . L-1), respectively. Confocal experiments showed that 10 mu mol . L-1 lumbrokinase showed no obvious effects on [Ca2+](i) at resting states (P > 0.05). However, the increase of [Ca2+](i) induced by 60 mmol . L-1 KCl was distinctly limited by 10 mu mol . L-1 lumbrokinase (P < 0.01). Within 240 s, the no obvious peak value of fluorescent intensity (FI) was shown. Conclusion Lumbrokinase showed protective action against myocardial infarction in rats. The possible mechanisms of anti-ischemia could be attributed to decreasing ICa-L and [Ca2+](i) of ventricular myocytes in rats.