1、 江南大学食品学院，江苏无锡 214122 2、 江南大学医学院，江苏无锡 214122
摘要：目的 探讨鼠源Cathelicidin家族抗菌肽CRAMP预处理对肾缺血再灌注损伤的影响及其作用机制。方法 8周C57BL/6雄鼠随机分成假手术组(Sham)、肾缺血再灌注组(IRI)和CRAMP预处理组。双侧肾蒂夹闭法建立肾缺血再灌注模型，再灌注24h后收集小鼠血液及肾组织，CRAMP组小鼠肾缺血前1h腹腔注射CRAMP，Sham组和IRI组注射等体积生理盐水。检测造模前后小鼠血清和肾脏中CRAMP的蛋白水平；检测小鼠肾功能（肌酐、尿素氮），小鼠肾组织HE染色；流式细胞术检测肾脏中性粒细胞比例；Q-pcr法检测肾脏中白介素(IL)-6和肿瘤坏死因子（TNF）-α 的mRNA水平；原位末端标记法(TUNEL)法检测肾脏凋亡细胞，Western blotting检测肾脏中Bax、BCL-2蛋白表达情况。结果 IRI组小鼠体内抗菌肽的表达量较sham组有明显下降；与IRI组相比，CRAMP预处理后肌酐、尿素氮水平明显降低，肾小管细胞坏死情况明显减少，肾脏中性粒细胞比例显著下降，IL-6和TNF-α的mRNA水平明显降低，肾脏凋亡细胞数明显减少，Bax／Bcl-2比值明显降低。结论 CRAMP参与到肾缺血再灌注的病理过程中，CRAMP干预可有效缓解小鼠肾缺血再灌注引起的急性肾损伤，其作用机制可能与调节中性粒细胞与炎症因子释放，减轻缺血再灌注诱导的肾脏细胞凋亡有关。
Cathelicidin-related antimicrobial peptide (CRAMP) prevent acute kidney injury induced by ischemia-reperfusion in mice
1、 School of Food Science and Technology, Jiangnan University, WuXi, Jiangsu 214122, China 2、 School of Madicine, Jiangnan University, WuXi, Jiangsu 214122, China
Abstract： Objective: To investigate the effect of Cathelicidin-related antimicrobial peptide (CRAMP) on acute kidney injury induced by ischemia–reperfusion(IR) and its possible mechanism in mice. Methods: 8 weeks male C57BL/6 mice were randomly divided into Sham group, IRI group and CRAMP treatment group. The bilateral renal arteries of the mice were clamped and then opened to establish the renal IRI model. The blood and kidneys were collected at 24 hours after reperfusion. CRAMP was administered intraperitoneally 1 hour before IRI, the mice in control group and IRI group were inject with equivalent volume of normal saline. We first examined CRAMP expression in serum and kidney tissues from Sham and IRI group; Renal function was evaluated by serum creatinine and urea levels; HE staining of kidney tissue; The percentage of neutrophils in kidney was tested by flow cytometry and the mRNA levels of IL-6 and TNF-α were examined by Q-pcr; Apoptosis in kidney tissue was observed with TUNEL staining and protein expression of Bax and Bcl-2 in renal were detected with Western blotting assay. Results: Compared with Sham group, CRAMP expression was dramatically decreased in the serum and kidneys. Exogenous CRAMP significantly attenuated renal I/R-induced injury. Compared with IRI group, the mice in CRAMP treatment group presented significant decreases in serum creatinine and urea nitrogen production and reduced necrosis in kidney tubular cells. The percentage of neutrophil in kidney tissues decreased significantly and the mRNA levels of IL-6 and TNF-α also declined in CRAMP group. TUNEL staining shows that CRAMP significantly reduced I/R-mediated apoptosis in kidney tissue and the ratio of Bax／BCL-2 decreased obviously in CRAMP group. Conclusion: CRAMP was involved in renal I/R injury, exogenous CRAMP efficiently reduced renal I/R-induced injury, the mechanism might involve in regulating neutrophil infiltration and related inflammatory cytokines expression, reducing I/R-mediated apoptosis.