Study about the elucidation of hepatocarcinogenesis mechanism km fatty liver and preventive strategies based on pathogenic considerations

本研究选用FLS小鼠（n=48）。无肥胖的FLS小鼠慢性自发性脂肪肝。肝脏肿瘤发生在1岁以后。FLS小鼠再分为3组：1组饲喂单独的对照饲粮（CA-1）， 2组饲喂含有乳酸菌的饲粮，3组饲喂含丁酸梭菌的对照饲粮，丁酸梭菌经口服后在肠道内产生丁酸。10月龄时，所有小鼠肝脏均有明显脂肪沉积，无纤维化。12月龄时，1组8只小鼠中有2只发生肝脏肿瘤，而2组和3组8只小鼠中均有1只发生肝脏肿瘤。高效液相色谱法测定小鼠粪便中的短链脂肪酸，结果显示，3组小鼠的丁酸钠浓度升高。10月龄LPS小鼠肝脏免疫组化分析显示，与3组小鼠相比，1组小鼠肝脏氧化应激标志物4-HNE显著升高。Western blot结果显示，3组小鼠肝脏中转录因子NF-KB蛋白表达增加。第3组小鼠肝脏中c-jun （Ser 73）也出现磷酸化。Western blot结果显示，3组小鼠肝脏p21 WAF1蛋白表达也明显升高。这些结果表明氧化应激在FLS小鼠肝脏疾病的进展中起着至关重要的作用。口服丁酸梭菌可保护FLS小鼠肝脏肿瘤的发生。

We used FLS mice (n=48) in this study. FLS mouse develops spontaneously fatty liver chronically without obesity. Liver tumors develop after age of 1 year. The FLS mice were subdivided into three groups : group 1 received control diet (CA-1) alone, group 2 received diet containing lactobacillus, and group 3 received control diet containing clostridium butyricum that produce butyric acid in a bowel after oral intake.At age 10 month, all mice showed significant fatty deposition in the liver without fibrosis. At age 12 month, 2 out of 8 mice in group 1 developed liver tumor, whereas 1 out of 8 mice developed liver tumor in both group 2 and 3. Measurement of short chain fatty acid in the feces by HPLC revealed that concentration of sodium butyrate increased in the mice of group 3.Immunohistochemical analysis of the liver of 10-month-old LPS mice showed that 4-HNE, a marker of oxidative stress, remarkably increased in group 1 mice compared with those in group 3 mice. On the contrary, the protein expression of transcription factor NF-KB increased in the liver of group 3 mice by the Western blot analysis. Phosphorylation of c-jun (Ser 73) was also observed in the liver of mice in group 3. Finally, protein expression of p21 WAF1 also increased in the liver of group 3 mice by the Western blot.These results indicate that oxidative stress takes a crucial role in the progression of liver disease in FLS mice. Oral intake of clostridium butyricum may protect the development of liver tumor in FLS mice.