灯盏花素调控MICA基因表达对人肾小管上皮细胞缺氧再给氧损伤的保护作用

The protective effects of breviscapine on human renal proximal tubular epithelial cells during hypoxia/re-oxygenation injury via regulating MICA expression

目的观察灯盏花素提取液对人肾小管细胞(HK-2)缺氧再给氧(hypoxia/re-oxygenation,H/R)损伤的保护作用,探讨其可能的治疗作用及保护机理。方法建立HK-2体外H/R损伤模型。随机分为3组:对照组、缺氧组、灯盏花素组(灯盏花素预处理+缺氧)。在缺氧16 h后设立4个时间点:复氧0、4、8、16 h。倒置显微镜下观察细胞的形态学改变,荧光定量和流式检测各组HK-2 MICA分子和蛋白水平的表达,乳酸脱氢酶释放法测定NK细胞对HK-2的杀伤能力。结果与对照组相比,缺氧组HK-2细胞MICA转录水平和蛋白表达水平在缺氧16 h后显著升高,于复氧8 h达峰值后逐渐下降,并于复氧16 h后恢复正常。NK细胞对H/R处理的HK-2细胞的杀伤活性与MICA的表达变化呈正相关。与缺氧组相比,灯盏花素组显著降低H/R处理的HK-2细胞MICA的表达和NK细胞对其的杀伤活性。结论在IRI过程中,下调H/R处理的HK-2细胞的MICA,从而抑制NK细胞对其的杀伤活性,可能是灯盏花素抗氧化应激和增强抗氧化防御功能的有效机制之一。

This study designed to investigate the protective role of breviscapine on human renal proximal tubular epithelial cells（HK-2） and its relative mechanism during hypoxia/re-oxygenation（H/R）. Firstly, ischemia/reperfusion（I/R） injury（IRI） was mimicked through establishing a HR model of HK-2 cells in vitro. HK-2 cells were randomly divided into three groups： control, H/R group and breviscapine treated group（breviscapine pretreatment ＋ H/R）. Sixteen hours after hypoxia, HK-2 cells were reoxygenated for 0, 4, 8, 16 h respectively under normal condition. Quantitative real time PCR and flow cytometry indicated that H/R significantly increased the levels of MICA mRNA and protein levels on HK-2, while lactate dehydrogenase（LDH） release assay demonstrated that H/R enhanced NK cell cytotoxic activity towards HK-2. Administration of breviscapine significantly reduced the mRNA and protein levels of MICA in I/R HK-2, and then significantly decrease the NK cell cytotoxicity activity. Thus, we concluded that breviscapine can significantly reduce NK cell cytotoxicity activity against HK-2undergoing I/R, and the mechanism may relate with down-regulating of MICA expression.