Department of Internal Medicine, Eulji General Hospital, Eulji University College of Medicine, Seoul, Korea.
BMC Nephrol. 2013 May 17;14:105. doi: 10.1186/1471-2369-14-105.
Bilirubin (BIL) has been recognized as an endogenous antioxidant that shows a protective effect for cardiorenal diseases. We investigated whether administration of BIL had a protective effect on cyclosporine (CsA)-induced nephropathy (CIN), and examined the effects of BIL on the oxidative stress and apoptosis.
BIL was pretreated intraperitoneally three times for a week (60 mg/kg), and CsA was injected for 4 weeks (15 mg/kg/day, subcutaneous). Proximal tubular epithelial (HK2) cells were pretreated with 0.1mg/ml of BIL for 24 hours, and then treated with 20 μM of CsA for another 24 hours.
CsA induced marked increases in urine kidney injury molecule-1 (Kim-1) and neutrophil gelatinase-associated lipocalin (NGAL) concentrations (P < 0.05). BIL reduced urine Kim-1 in CIN (P < 0.05), while urine NGAL exhibited a decreasing tendency. In CsA-treated rat kidneys, the protein expression of NOX4 and p22phox was reduced by BIL (P < 0.05). BIL ameliorated CsA-induced arteriolopathy, tubulointerstitial fibrosis, tubular injury, and the apoptosis examined by TUNEL assay (P < 0.01). In HK2 cells, BIL reduced intracellular reactive oxygen species in CsA-treated cells. CsA increased the protein expression of bax, cleaved caspase-9, caspase-3 and the activity of caspase-3; however, the anti-apoptotic bcl-2 protein was reduced. These changes were recovered by BIL (P < 0.05).
The direct administration of BIL protected against CsA-induced tubular injury via inhibition of oxidative stress and apoptosis.
胆红素（BIL）已被认为是一种内源性抗氧化剂，对心肾疾病具有保护作用。我们研究了胆红素（BIL）给药是否对环孢素（CsA）诱导的肾病（CIN）具有保护作用，并研究了 BIL 对氧化应激和细胞凋亡的影响。
BIL 经腹腔预处理 3 次，每周 1 次（60mg/kg），CsA 注射 4 周（15mg/kg/天，皮下）。近端肾小管上皮（HK2）细胞用 0.1mg/ml 的 BIL 预处理 24 小时，然后用 20μM 的 CsA 再处理 24 小时。
CsA 诱导尿肾损伤分子-1（Kim-1）和中性粒细胞明胶酶相关脂质运载蛋白（NGAL）浓度显著增加（P<0.05）。BIL 降低 CIN 中的尿 Kim-1（P<0.05），而尿 NGAL 呈下降趋势。在 CsA 处理的大鼠肾脏中，BIL 降低了 NOX4 和 p22phox 的蛋白表达（P<0.05）。BIL 改善了 CsA 诱导的小动脉病变、肾小管间质纤维化、肾小管损伤和 TUNEL 检测到的细胞凋亡（P<0.01）。在 HK2 细胞中，BIL 减少了 CsA 处理细胞中的细胞内活性氧。CsA 增加了 bax、cleaved caspase-9、caspase-3 的蛋白表达和 caspase-3 的活性；然而，抗凋亡的 bcl-2 蛋白减少。这些变化通过 BIL 得到恢复（P<0.05）。
BIL 的直接给药通过抑制氧化应激和细胞凋亡来防止 CsA 诱导的肾小管损伤。
