caspase-3和caspase-8在铅中毒大鼠心肌细胞中的表达特点研究

Expression Characteristics of Caspase-3 and Caspase-8 in Cardiomyocytes Rats of Lead Poisoning

目的构建铅中毒大鼠模型,观察心脏中半胱氨酸天冬氨酸蛋白酶-3(cysteinyl aspartate specific proteinase-3,caspase-3)和半胱氨酸天冬氨酸蛋白酶-8(cysteinyl aspartate specific proteinase-8,caspase-8)蛋白及mRNA的表达特点。方法 40只SD(Sprague Dawley)大鼠在适应性喂养2周后采用数字表法随机分为正常组(无铅水)、低剂量铅中毒组(0.5g/L醋酸铅水溶液)、中剂量铅中毒组(1g/L醋酸铅水溶液)和高剂量铅中毒组(2g/L醋酸铅水溶液),中毒1个月后处死,收集血液和心脏,检测血铅、心铅、心功能指标[肌酸激酶(creatine kinase,CK)、肌酸激酶同工酶(creatine kinase isoenzyme,CK-MB)和乳酸脱氢酶(lactate dehydrogenase,LDH)]、血清炎性指标[肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)、白介素-6(interleukin-6,IL-6)和白介素-8(interleukin-8,IL-8)]和心肌caspase-3和caspase-8蛋白及mRNA的表达特点。结果心肌组织病理学显示,正常组心肌纤维排列整齐,低剂量铅中毒和中剂量铅中毒组有一定紊乱,高剂量铅中毒组则明显排列无序,细胞界限不清晰;与正常组比较,低剂量、中剂量和高剂量铅中毒组血铅、心铅、TNF-α、IL-6和IL-8明显升高(P<0.05),与低剂量铅中毒组比较,中剂量和高剂量铅中毒组血铅、心铅、TNF-α、IL-6和IL-8明显升高(P<0.05),此外高剂量铅中毒组血铅、心铅、TNF-α、IL-6和IL-8也明显高于中剂量铅中毒组(P<0.05);与正常组比较,低剂量和中剂量铅中毒组CK、CK-MB、LDH、caspase-3与caspase-8蛋白和mRNA表达差异无统计学意义,高剂量铅中毒组明显升高(P<0.05),此外高剂量铅中毒组明显高于低剂量和中剂量铅中毒组(P<0.05)。结论 2g/L醋酸铅水溶液中毒大鼠可引起其心肌中caspase-3和caspase-8表达异常,诱发血液炎性介质TNF-α、IL-6和IL-8的升高,最终造成心肌损伤。

Objective To build the different lead poisoning rat models, observe the protein and mRNA expression of cysteinyl aspartate specific proteinase-3(caspase-3) and cysteinyl aspartate specific proteinase-3(caspase-8) in cardiac tissue. Methods Forty SD rats were randomly divided into the normal group(no lead water), low dose(0.5 g/L acetate solution), medium dose(1 g/L lead acetate solution) and high-dose lead exposure group(2 g/L lead acetate solution).All rats were received 1 months of lead exposure. After their blood and heart were collected, we detected the blood lead, heart lead, heart function[creatine kinase(CK), creatine kinase isoenzyme(CK-MB) and lactate dehydrogenase(LDH)], serum inflammatory[tumor necrosis factor-α(TNF-α), interleukin-6(IL-6) and interleukin-8(IL-8)] index and the expression characteristics of caspase-3 and caspase-8 protein and mRNA. Results The myocardial histopathology showed that the slices in the normal group was neatly arranged. The myocardial fiber was arrangement in the low-dose and medium-dose lead exposure groups, while in the high-dose lead exposure group it was obviously disordered and the cell boundaries were unclear. Compared with the normal group, the blood lead, heart lead, TNF-α, IL-6 and IL-8 in the low-dose, medium-dose and high-dose lead exposure groups were significantly increased(P<0.05). Compared with low-dose group, the blood lead and heart lead, TNF-α, IL-6 and IL-8 were significantly increased in the medium and high-dose lead exposure groups(P<0.05). Compared with the normal group, the cardiac function indexes CK, CK-MB and LDH, caspase-3 and caspase-8 mRNA and protein had no difference in the low-dose and medium-dose groups, but those indexes in the high-dose group was significantly higher(P<0.05), and those in the high-dose group was significantly higher low-dose and medium-dose group(P<0.05). Conclusion The 2 g/L acetate solution lead exposure given rats 1 mouth can cause abnormal expression of the caspase-3 and caspase-8 in rat myocardial tissue, increase the blood TNF-α, IL-6 and IL-8, which leads to the myocardial injury.