Objective To investigate the effect of small interfering RNA (siRNA) suppressing discoidin domain receptor 1 (DDR1) gene on biological behaviour of Kupffer cells (KC) in acute hepatic injury. Methods Male BALB/c mice were randomly divided into control, hepatic injury model, non-silencing siRNA and DDRlsiRNA groups. Hepatic injury model induced by intravenous injection of Con-canavalinA (ConA) 15 mg/kg, with or without hydrodynamic tail intravenous injection of naked siRNA (50 μg,2.0-2.5 mg/kg)/mouse or 1.5 ml normal saline. The expression of DDRI was assayed by West-ern blot and pro-inflammatory cytokine expression analyzed by ELISA. In the meantime, alanine amin-otransferase (ALT) and Kupffer cells'clearance to carbon granules was detected. Results The expres-sion of DDR1 obviously increasod at 6 h after hepatic injury, roached peak at 24 h and began to decrease at 48 h. Pretreatment with DDRisiRNA could obviously inhibit the expression of DDR1 and abrogate the high levels of ALT, expressions of TNF-α and IL-1β as well as phagocytosis of Kupffer cells. Conclu-sions Inhibition of discoidin domain receptor 1 by in vivo delivery of siRNA attenuates ConA-induced hepatic injury. Possible mechanism is that the inhibition of activity of KC inhibits the expression of pro-in-flammatory cytokines and thus alleviates hepatic injury.%目的 观察体内注射小干扰RNA(siRNA)技术抑制盘状结构域受体1(DDR1)在急性肝损伤时对枯否细胞(KC)功能的影响. 方法 雄性BALB/c小鼠随机分为对照组、肝损伤模型组、Non-silencing siRNA和DDR1siRNA处理组.采用静脉注射刀豆蛋白A(ConA)15 ms/kg诱发小鼠特异性肝损伤模型,按分组情况给予或不给予尾静脉高压注射裸siRNA(50 μg,2.0～2.5 ms/kg)或等渗盐水.Western印迹法分析DDRl蛋白表达变化、ELISA法检测肝内促炎性细胞因子的表达,同时检测血浆丙氨酸氨基转移酶(ALlT)活性和KC的吞噬功能. 结果 肝脏DDR1蛋白在肝损伤早期6 h才开始明显增高,24 h达到高峰,48 h后又逐渐减少.提前给予DDR1siRNA后明显抑制DDR1蛋白表达,刚时抑制了KC吞噬指数、ALT活性的升高和促炎性细胞因子TNF-α、IL-1β的表达. 结论 采用体内siRNA技术抑制DDRl在肝脏中的表达,可以明显减轻ConA诱发的小鼠特异性肝损伤,其机制可能是通过抑制KC活化减少了炎性细胞凶子的表达,从而减轻了后期肝免疫性损伤.
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