摘要
目的探讨不同水平高胆红素血症对新生大鼠心肌的影响。方法选取7日龄新生SD大鼠96只,随机分为对照组(n=32,腹腔注射生理盐水0.5 ml)、实验1组(n=32,腹腔注射胆红素溶液100 mg/kg)和实验2组(n=32,腹腔注射胆红素溶液200 mg/kg)。分别设置0 h、8 h、24 h和48 h 4个时间点,每个时间点8只大鼠。记录大鼠一般情况,测定每个时间点大鼠血清总胆红素(total serum bilirubin,TSB)、心肌肌钙蛋白Ⅰ、心型脂肪酸结合蛋白和B型利钠肽水平;摘取心脏,制作病理切片,镜下观察心肌病理学改变;检测半胱氨酸蛋白酶3(caspase-3)、B细胞淋巴瘤2(B-cell lymphoma-2,bcl-2)和bcl-2相关X蛋白(bcl-2-associated X protein,bax)。应用SPSS 20.0统计软件分析,选用两因素方差分析法。结果在实验1组内和实验2组内,8~48 h TSB[(20.8±3.0~36.5±10.4)μmol/L和(31.9±12.3~67.4±19.0)μmol/L]比0 h[(8.4±2.1)μmol/L和(9.1±2.9)μmol/L]分别升高2.5~4.4倍和3.5~7.4倍。在各时间点3组大鼠心脏组织病理均无明显改变。在48 h时间点,随着TSB水平升高,凋亡相关蛋白caspase-3和bax表达增加,bcl-2表达减少;除实验1组bcl-2灰度值与对照组相似(P=0.255)外,其余各组蛋白灰度值两两比较,差异均有统计学意义(P<0.05)。在实验2组,随着高胆红素血症持续时间延长,caspase-3和bax表达增加,bcl-2表达减少;除8 h亚组bax灰度值与12 h亚组相似(P=0.820)、8 h亚组bcl-2灰度值与0 h亚组相似(P=0.064)外,其余各时间点蛋白灰度值两两比较,差异均有统计学意义(P<0.05)。在8 h、24 h和48 h,实验1组和实验2组心肌肌钙蛋白Ⅰ均高于对照组[(543.5±167.7、675.1±162.4、584.4±125.2)ng/L和(465.7±107.2、769.4±202.1、497.1±100.8)ng/L比(361.7±102.4、324.5±170.5、377.8±65.2)ng/L],差异均有统计学意义(P<0.05),实验1组和实验2组之间差异均无统计学意义(P>0.05)。在各时间点3组间心型脂肪酸结合蛋白和B型利钠肽差异均无统计学意义(P>0.05)。结论高胆红素血症能诱导新生大鼠心肌细胞凋亡,且呈浓度和时间依赖性,但对大鼠心脏组织病理结构无明显影响;高胆红素血症对新生大鼠心肌有轻微损伤,但损伤程度与TSB升高程度无相关性,且对大鼠B型利钠肽无明显影响。
Objective To study the influences of different levels of hyperbilirubinemia on the myocardium of newborn rats.Methods Ninety-six 7-day-old newborn SD rats were selected and randomly assigned into control group(n=32,intraperitoneal injection of normal saline 0.5 ml),test group 1(n=32,intraperitoneal injection of bilirubin solution 100 mg/kg)and test group 2(n=32,intraperitoneal injection of bilirubin solution 200 mg/kg).Four time points were set at 0 h,8 h,24 h and 48 h.The general conditions of 8 rats from every group at each time point were recorded.The total serum bilirubin(TSB),cardiac troponin I(cTnI),heart fatty acid-binding protein(H-FABP)and B-type natriuretic peptide(BNP)were examined.The heart was removed and the pathological changes of the myocardium were observed under microscope.The caspase-3,B-cell lymphoma-2 protein(bcl-2)and bcl-2-associated X protein(bax)were tested.Using SPSS 20.0 statistical software,two-way ANOVA analysis of variance was conducted.Results The TSB in test group 1 and 2 at 8~48 h were 2.5~4.4 times and 3.5~7.4 times higher than at 0 h[(20.8±3.0~36.5±10.4)μmol/L and(31.9±12.3~67.4±19.0)μmol/L vs.(8.4±2.1)μmol/L and(9.1±2.9)μmol/L].No significant changes existed in cardiac histopathology at each time point among the three groups.At 48 h,as TSB level increased,the expression of apoptosis-related proteins caspase-3 and bax increased and the expression of bcl-2 decreased.Significant differences existed in the protein levels between any two groups(all P<0.05),except that bcl-2 in test group 1 was similar to control group(P=0.255).With the prolonged duration of hyperbilirubinemia in test group 2,the expression of caspase-3 and bax increased,while the expression of bcl-2 decreased.Statistically significant differences existed in the protein levels between any two time points(all P<0.05),except that bax in 8 h subgroup was similar to 12 h subgroup(P=0.820),and bcl-2 in 8 h subgroup was similar to 0 h subgroup(P=0.064).The cTnI at 8 h,24 h and 48 h in test group 1 and 2 were all significantly higher than the control group(all P<0.05),however,no significant differences existed between test group 1 and 2(all P>0.05).H-FABP and BNP showed no significant differences among the three groups at any time point(all P>0.05).Conclusions Hyperbilirubinemia can induce apoptosis of myocardial cells in newborn rats in a concentration-and time-dependent manner.Hyperbilirubinemia shows no significant effects on cardiac tissue pathology.Hyperbilirubinemia may cause mild injury to myocardium of newborn rats.The injury shows no correlation with TSB level and BNP level was not influenced.
作者
苏敏
王惠颖
任漪
李丽
赵丹丹
黄迪
杨波
高翔羽
Su Min;Wang Huiying;Ren Yi;Li Li;Zhao Dandan;Huang Di;Yang Bo;Gao Xiangyu(Department of Neonatology,Xuzhou Central Hospital(The Xuzhou Clinical College of Xuzhou Medical University),Xuzhou 221009,China)
基金
江苏省青年医学重点人才项目(QNRC2016384)。
关键词
高胆红素血症
心肌
利钠肽
脑
大鼠
Hyperbilirubinemia
Myocardium
Natriuretic peptide,brain
Rats
