COMBINED TRETMENT OF TRIPTOLIDE AND EMODIN INHIBITS THE PROGRESSION OF ANTI-GBM NEPHRITIS IN RATS
DAI Chunsun,LIU Zhihong,CHEN Huiping,ZHOU Hong,WANG Jianping,LI Leishi
(Research Institute of Nephrology,Jingling Hospital,Nanjing University Clinical School of Medicine,Nanjing,210002)
OBJECTIVE To investigate the therapeutic effects of combined treatment of triptolide and emodin in preventing the progression of anti-GBM nephritis in rats.METHODOLOGY Autologous anti-GBM nephritis model was elaborated with rabbit anti-rat GBM antibody(Ab) injection in Wistar rat in this study.The rats were divided into five groups:Triptolide treated group(200 μg/kg·d-1,po),Emodin treated group(200 mg/kg·d-1,po),Combined treatment group,Untreated nephritic group and Normal control.Triptolide and/or emodin were administered daily six hours after injection of anti-GBM IgG.All the rats were sacrificed and kidney specimen were collected at the fourth week.Urinary protein excretion rate was examined weekly.RESULTS (1)Rats injected with rabbit anti-rat GBM Ab excreted heavy proteinuria(202.4±77.3 vs 2.0±0.8 mg/24h,P<0.01) in the first 24 hours,that mantained at this high level during the observation period.At the end of the observation,glomerular hypercellulity,crescents,protein casts and mild increase of serum creatinine were observed in nephritic rats.Immunofluoresence staining revealed that rabbit IgG deposited in a “linear”pattern at glomerular GBM one day after injection.(2)In three treatment groups,urinary protein excretion,glomerular hypercellularity and crescents decreased significantly at the end of the experiment.Among the three treatment groups,the reduction of urinary protein excretion and glomerular crescent formation was most prominent in the combined treatment group.No difference was found in body weight change and serum creatinine concentration among the three treatment groups.CONCLUSION Emodin and triptolide inhibited the progression of rat anti-GBM nephritis alone,combined usage of these two agents was more efficient.
Key words emodin triptolide anti-GBM nephritis
肾小球肾炎是临床上最常见的一类肾脏疾病,是导致患者进入终末期肾衰的重要原因[1]。其发病机制较为复杂,早先人们认为,免疫因素(包括体液免疫及细胞免疫)的介入,机体通过补体途径的激活,血凝机制的起动,促炎介质、细胞因子的合成,蛋白酶以及促炎脂质的释放等造成了肾小球肾炎的发生与发展[2]。现在发现,除了免疫性因素外,肾固有细胞(如肾小球系膜细胞等)的活化及大量细胞因子与促炎介质的产生,可以进一步加重肾组织的损伤[3,4]。
雷公藤内酯醇是雷公藤二萜化合物中免疫抑制作用最强的单体,体外可以抑制有丝分裂原刺激的淋巴细胞增生反应,诱导活化的淋巴细胞发生凋亡[5],并通过抑制淋巴细胞NF-κB的活力而减少多种促炎因子(如IL-1,TNF-α等)及细胞因子的产生[6]。在肾移植大鼠模型中应用雷公藤内酯醇可以抑制移植肾急性排斥反应的发生,减少肾间质淋巴细胞的浸润[7]。大黄素是从大黄蒽醌衍生物分离出的一种单体,体外有很强的抑制肾固有细胞(如系膜细胞)增生的能力,也可以减少系膜细胞细胞外基质的表达与产生[8]。由于大黄素与雷公藤内酯醇在治疗肾小球肾炎中的不同药理作用方式,因此设想如果应用这两种药物同时阻断导致肾小球肾炎发生与发展的两个主要环节,应有助于提高肾小球肾炎的治疗水平。
本研究建立大鼠抗肾小球基底膜(GBM)肾炎模型,联合应用雷公藤内酯醇与大黄素对肾炎模型进行治疗,并设单用雷公藤内酯醇及大黄素治疗组,结合大鼠24h尿蛋白排泄量,以及肾组织病理的变化,观察两药联用在治疗该肾炎模型中的疗效。
1材料与方法
1.1药品大黄素经正品掌叶大黄(甘肃省西宁市药材公司)提取。由本院中心仪器科提供,经HPLC检测纯度均在90%以上。雷公藤内酯醇由中国医学科学院皮肤病研究所提供,检验纯度在99%以上。大黄素用前以10%乙醇溶解,并用生理盐水稀释至所需浓度,雷公藤内酯醇用前由吐温80溶解,并用生理盐水稀释。
1.2动物实验动物采用清洁级Wistar大鼠,购自上海动物实验中心。实验期间,动物室温度25~28℃,湿度70%,12h交替照明,大鼠自由饮水、进食,保持垫料干糙。饲料中蛋白含量为20%。
1.3大鼠抗GBM肾炎模型制备参照Shreiner方法建立大鼠抗GBM肾炎模型[9],具体方法包括以下步骤:
1.3.1大鼠GBM抗原制备取成年Wistar大鼠80只,雌雄不限。麻醉后暴露腹腔,经腹主动脉插管,用冷PBS液对双肾进行充分灌洗后取肾脏,将皮质剪碎后分别过50,100及200目网筛,最后留在200目网筛上的即为肾小球。收集肾小球,用超声粉碎机将肾小球充分粉碎后以14 000 r/min,离心10min,弃上清,沉淀用生理盐水溶解,测蛋白质含量为3 g/L,-20℃冰箱保存备用。
1.3.2兔抗鼠GBM抗血清制备及IgG的提纯健康成年新西兰兔,雄性,体重1.5~2kg,取1ml GBM溶液与等量弗氏佐剂充分混匀后于兔背部皮下多点注射,每两周一次,首次用弗氏完全佐剂,第二次用弗氏不完全佐剂,以后单用抗原,并且每次注射抗原前测血清抗GBM抗体的滴度,滴度合适后一周,经颈动脉放血。分离血清,用等量的新鲜大鼠红细胞吸附,4℃过夜,采用饱和硫酸铵沉淀法分离提纯IgG。测IgG浓度为25g/L。总量为120ml。同时取正常新西兰兔,制备正常兔IgG,浓度为23g/L,-20℃冰箱保存。
1.3.3大鼠抗GBM肾炎模型的制备取Wistar雄性大鼠,体重130~150g,将正常兔IgG与弗式不完全佐剂充分混匀,制成油包水,以1mg/100g注入大鼠腹腔,第5天时经尾静脉注入适量肾毒血清(12.5mg/100g)。
1.4实验分组及给药注射肾毒血清后6h内开始灌胃给药,对照组给予等量的水。根据用药种类分为五组:A组(大黄素200mg/kg。d-1,n=6);B组(雷公藤内酯醇200μg/kg。d-1加大黄素200mg/kg。d-1,n=6);C组(雷公藤内酯醇200 μg/kg。d-1,n=6);D组(肾炎对照,n=8);E组(正常对照,n=6)。
1.5标本采集及检测
1.5.1普通标本实验开始后每周用金属代谢笼(上海动物实验仪器厂)收集24h尿液;每周用玻璃毛细管经大鼠内眦静脉采集血标本;24h尿蛋白定量采用考马斯亮兰G-250法检测;血肌酐及尿肌酐采用碱性苦味酸法检测。
1.5.2肾组织病理标本实验4周时宰杀大鼠取左肾,经肾门冠状面取组织厚约2mm,10%中性福尔马林固定,行石蜡包埋,组织切片行HE,PAS及PAM染色。光镜下观察肾小球及小管间质病变情况。同时取右肾,去除肾包膜及肾门区结缔组织后,用电子天平称取右肾重量。
1.5.3脾脏重量测定实验4周宰杀大鼠后,取脾脏,去除脾脏表面包膜及脾门周围结缔组织,用电子天平称取脾脏重量。
1.5.4免疫组化染色取肾组织方法同上,将组织块置于生理盐水浸湿的干净纱布中,于-20℃冰箱保存待检。免疫组化染色采用改良PAP四层法,具体方法如下:取冰冻切片,充分吹干,冷丙
