Histochemical study of transmyocardial laser channels in dogs

目的　了解激光心肌血运重建术时激光对心肌的损伤。方法　在狗心肌上用CO2 激光打孔。术后即刻、两周时于打孔处取材 ,用硝基蓝四唑法作琥珀酸脱氢酶、乳酸脱氢酶组织化学染色。结果　术后即刻 ,孔道及其周围心肌分为五个区。中央为孔道即组织汽化区 ,向外依次为碳化区、酶消失区、酶减少区、酶浓缩区。两周后孔道区被肉芽组织取代 ,周围心肌细胞酶活性正常。结论　激光心肌血运重建术术后即刻 ,孔道周围心肌细胞酶活性由内向外依次呈消失、减少、浓缩改变。术后两周可逆性损伤的心肌细胞酶活性恢复。

Histochemical study of transmyocardial laser channels in dogs

Objective Laser-induced myocardial injury was investigated in a canine transmyocardial laser revascularization model.Methods A total of 23 channels were created in the left ventricles of 5 animals with a CO(2)laser. Four animals were sacrificed immediately and one at week 2. Lactate dehydrogenase and succinate dehydrogenase in channel regions were examined with a Nitro-BT method staining.Results Immediately after the procedure, laser channels and surrounding injured myocardium could be stratified from the center to the border into 5 concentric zones, i.e., vaporized zone, carbonized zone, enzyme-disappeared zone, enzyme-decreased zone and enzyme-concentrated zone. Two weeks later, the phenomenon disappeared.Conclusions Immediately after transmyocardial revascularization, there is a ring of enzyme-concentrated zone at the outermost region of injured myocardium. Two weeks later, enzyme activities of reversibly injured myocytes appear to have recovered.