Fgl2在顺铂诱导的小鼠急性肾损伤中的作用及机制研究

The role of Fgl2 in cisplatin-induced mouse acute kidney injury and its mechanism

目的研究纤维蛋白原样蛋白2(fibrinogen-like protein 2,Fgl2)在顺铂诱导的小鼠急性肾损伤(cisplatin-induced acute kidney injury,Cis-AKI)中的作用及其机制。方法选取8~10周,雄性,体质量(20±2)g,C57BL/6背景的野生型的Fgl2^+/+和Fgl2基因敲除的Fgl2^-/-小鼠为研究对象。实验分为4组:Fgl2^+/+(Saline组)、Fgl2^-/-(Saline组)、Fgl2^+/+(Cis-AKI组)、Fgl2^-/-(Cis-AKI组)。Saline(0.9%生理盐水)组每组4只,Cis-AKI组每组6只。Cis-AKI组予以单次腹腔注射顺铂(20 mg/kg,200μl),Saline组予以相同体积及相同给药方式的0.9%生理盐水。72h后各组小鼠取眼球血,收集血清,断颈处死小鼠,获取肾脏组织。全自动生化分析仪检测血清肌酐(serum creatinine,Scr)及尿素氮(blood urea nitrogen,BUN);石蜡切片HE染色检测小鼠肾组织病理改变,实时定量PCR(qRT-PCR)检测小鼠肾组织中Fgl2、肾损伤分子1(kidney injury molecule-1,KIM-1)、中性粒细胞明胶酶相关脂质运载蛋白(neutrophil gelatinase-associated lipocalin,NGAL)、白细胞介素6(interleukin-6,IL-6)、单核细胞趋化蛋白1(monocyte chemoattractant protein-1,MCP-1)、肿瘤坏死因子α(tumor necrosis factor-α,TNF-α)、白细胞介素1β(interleukin-1β,IL-1β)及白细胞介素10(interleukin-10,IL-10)的mRNA水平;免疫组织化学染色法(immunohistochemistry,IHC)检测小鼠肾组织中Fgl2、CD45的表达;免疫印迹(Western blot)检测肾组织中Fgl2、p38、p-p38、p65、p-p65、裂解的半胱天冬酶-3(cleaved-caspase3)、裂解的半胱天冬酶-9(cleaved-caspase9)的蛋白水平;原位末端转移酶标记技术(terminal deoxynucleotidyl transferase-mediated dUTP nick end-labelling,TUNEL)检测小鼠肾小管上皮细胞凋亡;免疫荧光(immunofluorescence,IF)检测p-p65蛋白表达。结果Fgl2^+/+(Cis-AKI)组小鼠肾组织Fgl2表达较Fgl2^+/+(Saline)组显著升高。Cis-AKI组中,与Fgl2^+/+组相比,Fgl2^-/-组小鼠血清BUN、Scr显著升高;肾组织中KIM-1、NGAL的表达显著增加,肾脏组织病理损伤更严重;促炎因子TNF-α、MCP-1、IL-1β、IL-6表达及CD45+炎症细胞浸润显著增加,而抑炎因子IL-10表达减少;凋亡相关蛋白cleaved-caspase3、cleaved-caspase9表达和肾组织细胞凋亡明显增多,参与调控凋亡及炎症的NF-κB p-p65及p-p38 MAPK显著升高。结论Fgl2基因缺失恶化顺铂诱导的小鼠急性肾损伤,这可能与Fgl2缺失后炎症反应与凋亡加重有关。

This study was performed to investigate the role and mechanism of fibrinogen-like protein 2(Fgl2)in cisplatin-induced acute kidney injury(Cis-AKI).Wild type mice(Fgl2^+/+)and Fgl2 gene knockout mice(Fgl2^-/-)with the same background,gender and weight were selected,and Cis-AKI model was established by single intraperitoneal injection of cisplatin.Mice were divided into four groups:Fgl2^+/+(Saline),Fgl2^-/-(Saline),Fgl2^+/+(Cis-AKI)and Fgl2^-/-(Cis-AKI)groups.Mice in Fgl2^+/+(Cis-AKI)and Fgl2^-/-(Cis-AKI)groups were treated with cisplatin(20 mg/kg,200μl),while mice in Fgl2^+/+(Saline)and Fgl2^-/-(Saline)groups were treated with equal volume of 0.9%saline.Kidney tissues and serum were collected at 72 h after cisplatin injection.The levels of urea nitrogen and creatinine in serum were measured by automatic biochemical analyzer;renal pathology change was assayed by HE staining.qRT-PCR was used to detect the mRNA levels of Fgl2,KIM-1,NGAL,IL-6,MCP-1,IL-1β,IL-10 and TNF-αin kidney tissues of mice;Western blot was used to detect the expression levels of Fgl2,p38,p-p38,p65,p-p65,cleaved-caspase3 and cleaved-caspase9;IHC was used to detect the expression of Fgl2 and the count of CD45 positive cells in kidney tissues.The apoptosis of renal tubular cell was detected by TUNEL staining;the protein level of p-p65 was observed by immunofluorescence.Data showed that the Fgl2 expression was dramatically increased in kidney tissues from Fgl2^+/+(Cis-AKI)mice compared with Fgl2^+/+(Saline)mice.Compared with mice in Fgl2^+/+(Cis-AKI)group,Fgl2^-/-(Cis-AKI)mice showed a significant increase in the levels of Scr and BUN,tubular injury score,the proinflammatory factor mRNA levels of IL-6,MCP-1,IL-1β,TNF-α,and the count of CD45 positive cells,but a lower expression of IL-10.Moreover,Fgl2^-/-(Cis-AKI)mice presented higher protein levels of p-p38,p-p65,cleavedcaspase3 and cleaved-caspase9.In conclusion,Fgl2 deficiency aggravate cisplatin-induced acute kidney injury in mice by improving the inflammatory response and apoptosis.