Böhm F, Drygalla F, Charlesworth P, Böhm K, Truscott T G, Jokiel K
Humboldt University, Department of Dermatology (Charité), Berlin, Germany.
Photochem Photobiol. 1995 Dec;62(6):980-3. doi: 10.1111/j.1751-1097.1995.tb02397.x.
Phototherapy of newborn infants with blue or green light is the most common treatment of neonatal hyperbilirubinemia. Using bilirubin bound to human lymphoid and basal skin cells we obtained the green light dose dependency of the bilirubin phototoxicity to these cell types. Cells (3-5 x 10(6)/mL) were incubated with bilirubin complexed to human serum albumin (final concentrations 340 microM bilirubin, 150 microM albumin). Under these conditions all cells showed maximum binding of bilirubin. Irradiation with broadband green light (lambda max = 512 nm) over 24 h led to a light dose-dependent population of cells, which contained no bilirubin on the cell membrane as determined by Nomarski interference microscopy. The light-induced mechanism of the disappearance of bilirubin caused lethal membrane damage to the cells (trypan blue exclusion test). The cell kill rate increased with the irradiation dose and with the fraction of cells with no bilirubin. When 90% of lymphoid cells were bilirubin free, 46% of them were dead (using 480 J cm-1 green light). Similar results were obtained with basal skin cells. In addition, bilirubin-induced damage of cell membrane and nuclear membrane was also shown by transmission electron microscopy. Bilirubin (340 microM) in the dark led to 5% of the cells being killed. Basal skin cells bind 2.5 times more bilirubin molecules than lymphoid cells and showed a different bilirubin disappearance. Irradiation of bilirubin in carbon tetrachloride with 514.5 nm laser light showed generation of singlet oxygen via its luminescence at 1270 nm. These results demonstrate that green light phototherapy of hyperbilirubinemia may cause both skin and immune system damage.
用蓝光或绿光对新生儿进行光疗是新生儿高胆红素血症最常见的治疗方法。利用结合在人淋巴细胞和基底皮肤细胞上的胆红素，我们得出了胆红素对这些细胞类型的光毒性的绿光剂量依赖性。将细胞（3 - 5×10⁶/mL）与人血清白蛋白结合的胆红素一起孵育（最终浓度为340μM胆红素，150μM白蛋白）。在这些条件下，所有细胞都显示出胆红素的最大结合。用宽带绿光（λmax = 512nm）照射24小时导致细胞数量呈光剂量依赖性减少，通过诺马斯基干涉显微镜测定，细胞膜上不含胆红素。胆红素消失的光诱导机制对细胞造成了致命的膜损伤（台盼蓝排斥试验）。细胞杀伤率随照射剂量和无胆红素细胞比例的增加而增加。当90%的淋巴细胞无胆红素时，其中46%死亡（使用480J/cm²的绿光）。基底皮肤细胞也得到了类似的结果。此外，透射电子显微镜也显示了胆红素对细胞膜和核膜的损伤。黑暗中340μM的胆红素导致5%的细胞死亡。基底皮肤细胞结合的胆红素分子比淋巴细胞多2.5倍，并且显示出不同的胆红素消失情况。用514.5nm激光照射四氯化碳中的胆红素，通过其在1270nm处的发光显示产生了单线态氧。这些结果表明，高胆红素血症的绿光光疗可能会导致皮肤和免疫系统损伤。
