胆红素对新生儿脐血单核细胞凋亡的影响

Effects of bilirubin on the apoptosis index of cord blood monocyte in neonates

目的探讨胆红素对新生儿脐血单核细胞（CBMC）凋亡的影响。方法采用纤维连接蛋白结合法分离新生儿CBMC。经含有不同浓度胆红素（6mg／dl、9mg/dl、12．9mg／dl和18mg／dl）的牛血清白蛋白溶液孵育1h，再给予脂多糖（LPS，1μg／m1）刺激48h，收集细胞。采用TUNEL法检测细胞的凋亡率。结果LPS和低浓度（6mg／d1）胆红素单独作用对CBMC的凋亡率均无影响。低浓度胆红素（6mg／d1）与LPS共同作用不升高CBMC的凋亡率；较高浓度和高浓度胆红素（9mg／dl、12．9mg／dl、18mg／dl）与LPS共同作用可升高CBMC的凋亡率，且这种作用随胆红素浓度的升高而增加。结论较高浓度和高浓度胆红素可以升高CBMC的凋亡率，此种抑制作用可能与胆红素引起细胞膜破坏、Ca^2＋内流增多、线粒体功能障碍有关。

Objective To explore the effects of bilirubin on the apoptosis index （AI） of cord blood monocyte （CBMC）. Methods The CBMC of normal full-term neonates selected randomly as subjects was isolated by the method of gelatin/plasma coated flasks. The CBMC was preincubated with unconjugated bilirubin dissolved in bovine albumin solution at various concentration （6 mg/dl、9 mg/dl、 12. 9 mg/dl and 18 mg/dl）. Bilirubin-treated CBMC was further cultured with LPS for inducing cellular activation for 48 hours,and then the CBMC was collected. The AI of CBMC after cultivation was detected by using TUNEL methods. Results No differences of AI among the normal control group, LPS group and 6 mg/dl （free-LPS） group （ P 〉 0. 05 ） were found. In the presence of LPS, the AI of the 6 mg/dl group was similar to those of the normal control group,LPS group and 6 mg/dl （free-LPS） group （P 〉0. 05） ,while the AIs of the 9 mg/dl group, 12 mg/dl group and 18 mg/dl group were significantly higher than those of the normal control group, LPS group,6 mg/dl （free-LPS） group and 6 mg/dl group （ P 〈 0. 05 ）. The increase of the AI of CBMC was corresponding to the raise of the bilirubin concentration. Conclusion The bilirubin can increase the AI of CBMC by destroing the configuration of the cell membrane, increasing intracellular calcium concen- tration and inducing the mitochondrial energy failure.