Involvement Of MicroRNAin Isoniazid-induced Liver Injury In Mice

Objectives We detect the expression of miR-122/155and the indexes of oxidative stressin liver injury in mice, by the administration of isoniazid, a first-line antituberculosis drug.And we analyze the relationship of miR-122/155and oxidative stress during thedevelopment of anti-tuberculosis liver injury (ADLI), which could make a contribution forsearching a new biomarker and pathogenesis of earlyADLI.Methods1) Acute toxicity experiment:(1) Animal experiment: Blood and liver tissuesamples were collected at0.25,0.75,1.5,6,12,18, and24h after administering INH(180mg/kg)(n=10per time point/treatment group) and physiological saline (n=10,control group). Blood and liver tissue samples were collected over time, afteradministration.(2) Experimental methods: Formalin-fixed samples were embedded withhematoxylin and eosin for microscopic examination. ALT and AST levels were determinedusing an automatic biochemical analyzer. The expression levels of miR-122/155weredetected by quantitative reverse transcription-PCR.(3) Data analysis: The data areexpressed as mean±SD. Statistical differences between groups were determined usingANOVA. Correlation analysis was performed using Pearman. Differences with P<0.05were considered statistically significant.2) Chronic toxicity experiment:(1) Animal experiment: Animal treated the same asacute toxicity experiment. In addition, blood and liver tissue samples were collected at1D,3D,5D,1W,2W,3W, and4W after administering INH (90mg/kg).(2) Experimentalmethods: microscopic examination, ALT, AST and miR-122were determined the same asacute toxicity experiment. CuZnSOD and MDA levels were determined using bybiochemical method. The protein of MT and MRPS11were detected by ELISA.(3) Dataanalysis: The same to acute.Results1) Acute toxicity experiment (1) Histopathology: The livers of the INH-treatedmice exhibited inflammatory cell infiltration since the0.25h time point.(2) Serumbiochemistry: The serum ALT and AST levels at0.75h after INH administration wasconsiderably higher than those at the other time points.(3) Changes in tissue miR-122/155:The miR-122levels began to decline at0.25h (56.50±27.77)%(P<0.05). The miR-155levels began to decline at0.75h (11.25±1.43)fold (P<0.05).(4) Correlations ofbiochemistry change: The best correlation coefficient of pathological score and ratio of miR-122/miR-155is-0.779(P<0.01).2) Chronic toxicity experiment:(1) Histopathology: The inflammatory cell infiltrat-ion were exhibited at3D time point after INH treated.(2) Serum biochemistry: The serumALT and AST levels at2W and3W after INH administration was significantly higher thanthose of the control group. CuZnSOD and MDA levels were significantly changed at5D(P<0.05).(3) miR-122: The miR-122levels began to decline at3D (88.72±5.15)%(P<0.05).(4) MT and MRPS11: The protein of MT and MRPS11were all significantchanged at3D after treated, and they all declined to lean at2W.(5) Correlations ofbiochemistry changes: The correlation coefficient of miR-122and MRPS11withCuZnSOD, MDA and MT (r=0.240, r=-0.311, r=0.415; P<0.05)(r=0.313, r=-0.250,r=0.366; P<0.05).Conclusion miRNA correlate with ADLI in acute/chronic toxicity test. The low or highexpression of miR-122and miR-155is relationship with the occurrence and developmentof ADLI. Hance, the ratio of miR-122/miR-155is expected to be an early diagnosticmarker for ADLI. And miR-122may be involved in the stress response by regulatingMRPS11of ADLI oxidation, which would be for the study of the pathogenesis ADLIprovide new experimental evidence.