斑蝥素引起小鼠急性膀胱炎的作用及相关机制

Effect of Cantharidin in Inducing Acute Cystitis in Mice

目的：探索斑蝥素（cantharidin,CTD）在1/2半数致死量（median lethal dose,LD50）条件下灌胃引起的小鼠急性膀胱炎的病理表现及其相关机制。方法：取Balb/c小鼠,分为空白组与CTD给药1~14 d组。给药组分别以CTD 1/2 LD50灌胃给药不同天数,空白组给予等量的0.5%的羧甲基纤维素钠溶液（CMC-Na）,最后1次给药3 h后取小鼠膀胱组织,用苏木素-伊红（HE）染色法分别检测CTD给药1~14 d小鼠膀胱的病理组织学变化,用蛋白免疫印迹法（Western blot,WB）检测CTD给药1 d组小鼠的膀胱组织中与炎症相关的信号通路中的蛋白表达情况。结果：HE染色结果表明,与空白组比较,斑蝥素给药1,3,8~12 d组膀胱组织病变比较明显,主要表现为黏膜上皮剥脱、黏膜上皮增生、固有层水肿或伴出血以及黏膜炎细胞浸润等组织炎症性病变。WB结果显示,与空白组相比,CTD给药1 d组,小鼠膀胱组织中磷酸化蛋白激酶B（p-Akt）,蛋白激酶B（Akt）蛋白,磷酸化的核转录因子-kappa B（p-NF-κB）p65蛋白,磷酸化的核转录因子kappa B的抑制蛋白alpha（p-IκBα）,IκBα蛋白表达水平上升（P〈0.01）。结论：CTD给药3 h即可引起小鼠急性膀胱炎,且给药前7 d机体对CTD导致的膀胱损伤尚有修复能力,给药8~14 d膀胱表现出不可逆且逐渐加重的炎症性病变,Akt信号通路及NF-κB信号通路的激活与CTD引起的急性膀胱炎存在一定相关性。

Objective： To explore the pathology and relevant mechanisms of cantharidin（CTD） in inducing acute cystitis in mice through intragastric administration under the condition of 1/2 median lethal dose（LD50）. Method： Balb/c mice were divided into control group and 1-14 day cantharidin administration groups.The administration groups were intragastrically given cantharidin at 1/2 LD50 for different days,while the control group was given the same amount of 0. 5% carboxymethyl cellulose sodium（CMCNa）. 3 h later after the last administration,bladders of 1-14 day cantharidin administration groups were collected for pathological detection by hematoxylin-eosin（HE） staining,and the bladder protein expressions of the 1 day cantharidin administration group was detected by Western blot（WB）. Result： Compared with the control group,1,3,8-12 day cantharidin administration groups showed mucosal epithelial exfoliation,mucosal epithelial hyperplasia,edema of the lamina propria with bleeding,and mucosal inflammatory cell infiltration in bladder. Western blot results showed that on the1 st day after cantharidin administration,levels of phosphorylatedprotein kinase B（p-Akt）,protein kinase B（Akt）,p-nuclear transcription factor-kappa B（NF-κB） p65,p-NF-κB inhibitor α（p-IκBα） and IκBαincreased significantly（P〈0. 01）. Conclusion： Acute cystitis in mice can be induced by the 3 h administration with cantharidin. After 1-7 day administration with the drug,the bladder injury caused by CTD could be repaired,but the bladder showed an irreversible and gradually aggravated inflammatory lesion on the 8-14 day. The activation of Aktsignaling pathway and NF-κB signal pathway is related to CTD-induced acute cystitis.