骨髓间充质干细胞移植对急性肝功能衰竭大鼠肝组织miRNA-155和TNF-α表达的影响

目的探讨骨髓间充质干细胞（BMSCs）移植对急性肝功能衰竭（ALF）大鼠肝组织中miRNA-155和TNF-α表达的影响,以及与BMSCs疗效间的关系。方法将SD大鼠随机分为健康对照组、ALF组、BMSCs治疗组和BMSCs预防组,其中ALF组予以900 mg/kg D-GalN＋10μg/kg脂多糖腹腔注射建立模型;BMSCs治疗组在900 mg/kg D-GalN＋10μg/kg脂多糖腹腔注射后2 h,予以尾静脉注射BMSCs 5.0×10^6;BMSCs预防组在900 mg/kg D-GalN＋10μg/kg脂多糖腹腔注射前予以尾静脉注射BMSCs 5.0×10^6;健康对照组予以0.9﹪氯化钠溶液1 ml腹腔注射。给药7 h后每组处死大鼠,检测大鼠血清ALT和AST,ELISA法检测TNF-α水平,实时定量PCR检测肝组织miRNA-155、TNF-αmRNA。各组间肝功指标差异采用方差分析,同时观察每组大鼠的24 h生存率,并用卡方检验比较各组生存率的差异。结果 D-GalN/脂多糖诱导7 h后,与ALF组相比,BMSCs预防和BMSCs治疗组大鼠ALT、AST、TNF-α水平均有所降低（P〈0.01）;同时两组肝组织TNF-αmRNA和miRNA-155表达水平均有下调（P〈0.01）;但两组间相比较差异无统计学意义。ALF组大鼠肝组织miRNA-155上调和TNF-αmRNA诱导呈正相关（r=0.734,P=0.001）。BMSCs预防组和BMSCs治疗组miRNA-155和TNF-αmRNA的部分逆转亦呈正相关（r值分别为0.687和0.590,P值分别为0.004和0.006）。给药后24 h,健康对照组、ALF组、BMSCs治疗组和BMSCs预防组大鼠死亡率组间比较差异有统计学意义（c2=19.078,P〈0.01）。结论在BMSCs干预大鼠ALF发病过程中,可以部分逆转上调的肝组织miRNA-155和TNF-α,且存在协同性,提示BMSCs治疗ALF可能通过对肝组织miRNA-155和TNF-α的调控发生作用。

Effects of bone marrow mesechymal stem cells on microRNA-155 and tumor necrosis factor alpha expression in liver tissue of rats with acute liver failure

Objective To explore the effects of bone mesenchymal stem cells（BMSCs） on the microRNA-155（miRNA-155） and tumor necrosis factor alpha（TNF-α） expression in liver tissue of rats with acute liver failure（ALF）, and to explore the relationship between miRNA-155/TNF-α and the efficacy of BMSCs. Methods SD rats were randomly divided into four groups, including control group, ALF group, BMSC treatment group and BMSC pretreatment group. Rats in each group were sacrificed 7 h after intraperitoneal D-GalN/LPS administration. Liver function, serum TNF-α level, miRNA-155 and TNF-α mRNA of liver tissue were detected subsequently. Survival rate at 24 h was observed in each group. Results Seven hours after D-GalN/LPS induction, alanine aminotransferase and aspartate aminotransferase levels of BMSC treatment and BMSC pretreatment groups were significantly lower when compared with those of ALF group（all P〈0.01）. Compared with ALF group, serum levels of TNF-α decreased in BMSC treatment and BMSC pretreatment groups and the difference was statistically significant（all P〈0.01）. The difference of the TNF-α mRNA expression in liver tissue between groups was statistically significant（F = 72.24, P〈0.01）. The TNF-α mRNA and miRNA-155 expression of BMSC treatment and BMSC pretreatment groups were down-regulated in comparison with ALF group, which showed statistical difference（all P〈0.01）. The positive correlation between miRNA-155 and TNF-α mRNA in liver tissue was confirmed in ALF group（r = 0.734, P = 0.001）, BMSC treatment（r = 0.590, P = 0.006） and BMSCs pretreatment（r = 0.687, P = 0.004）. 24 h after D-GalN/LPS administration, the difference of mortalities between groups was statistically significant（χ2=19.078, P〈0.01）. Conclusion With BMSC intervention in ALF, up-regulated miRNA-155 and TNF-α expressions in liver tissue could be partially reversed by BMSCs, suggesting that BMSC alleciate ALF via regulating miRNA-155 and TNF-α.