角蛋白18在33和52位丝氨酸磷酸化水平的变化及与肝纤维化的关系

The expression of Keratin 18 and its Ser33 and Ser52 Phosphorylation level changes in Liver fibrosis in mice

目的探讨角蛋白18(keratin18,K18)在33和52位丝氨酸(Ser)磷酸化水平变化的作用及其与肝纤维化的关系。方法 6周龄Balb/C小鼠30只,分为3组(对照组和2个实验组),每组10只。对照组腹腔内注射橄榄油;实验组腹腔内注射四氯化碳(CCl4)和橄榄油的混合液(1∶9),10 ml/kg,每周2次,连续4周,分别在2周和4周处死小鼠。应用组织化学免疫荧光法检测正常对照小鼠和肝纤维化小鼠肝组织中K18及其磷酸化Ser33和Ser52的表达及其相对亚细胞定位;免疫印迹法(Western blotting)检测正常对照小鼠和肝纤维化小鼠肝组织的K18及其磷酸化Ser33和Ser52水平。结果组织化学免疫荧光结果显示,K18在正常对照小鼠和肝纤维化小鼠肝组织中均有表达,但在小鼠肝纤维化不同阶段无明显差异;在正常对照小鼠肝组织中表达比较弱,而随着肝纤维化的进展表达增强。West-ern blotting结果,肝纤维化小鼠肝组织中的Ser33和Ser52磷酸化的K18表达水平显著增加,尤其是Ser33表达增加更为明显。

objective To investigate the relationship of Ser33 and Ser52 phosphorylated K18 and the progression of liver fibrosis. Methods Thirty 6-week Balb/C mice were selected and randomly divided into 3 groups,10 mice in each group. The control group was injected with olive oil. The experiment group was injected with 10 ml/kg body weight of a carbon tetrachloride（CCl4）/olive oil（OO） mixture（1：9） twice a week, half of the mice were sacrificed at week 2,4 after CCl4-treatment. The expression and locatization of K18 and Ser33 52 phosphorylated K18 of different progression level of liver fibrosis in mice was detected by immunohistochemistry. The protein expression of K18 and Ser33 52 phosphorylated K18 of liver fibrosis in mice were detected by Western blotting. Results The expression of K18 in the liver cells was not associated with progression of liver fibrosis in mice. The expression of Ser33 and Ser52 phosphorylated K18 in liver tissue of mice was relatively weak in the normal control group, but the expression of Ser33 and Ser52 phosphorylated K18 in liver fibrosis in mice was enhanced. The ser33 and ser52 phosphorylated K18 levels were significantly increased, especially the expression of ser33 was significantly increased in contrast to the healthy liver tissue of mice by Western blotting.Conclusion The phosphorylation of K18 may be a marker of progession of liver fibrosis in mice.