Objective To explore the protective mechanism of metformin against liver ischemia-reperfusion injury through microRNA(miRNA,miR)-19a.Methods 30 C57BL/6 mice were randomly divided into sham operation group,ischemia-reperfusion group,and metformin group by random number ta-ble method,10 mice/per group.Liver ischemia-reperfusion injury models were established in the ischemia-reperfusion group and metformin group mice,while no models were established in the sham surgery group mice.Metformin group mice received daily tail vein injection of 200 mg/kg metformin three days before surgery,and the administration was stopped 24 hours before surgery.The sham surgery group and ischemi-a-reperfusion group mice were injected with an equal volume of physiological saline via the tail vein before surgery.Three groups of mice were tested for serum alanine aminotransferase and aspartate aminotransferase concentrations using radioimmunoassay at 6 hours after surgery.Take liver tissue and screen for differential-ly expressed miRNAs using transcriptome analysis.The differential miRNA expression levels was analyzed by fluorescence quantitative polymerase chain reaction(PCR).MiR-19a target genes was analyzed by bioinformatics analysis.The levels of inflammatory factors in the liver of three groups of mice was analyzed by enzyme linked immunosorbent assay.The expression levels of silent information regulator 1(SIRT1),the target protein of miR-19a,and its downstream molecule Nuclear Transcription Factor(NF kB)were an-alyzed by Western blotting.The comparison of inter group measurement data was conducted using one-way analysis of variance.Results The serum levels of alanine aminotransferase and aspartate aminotransferase in the metformin group mice[(120.16±14.67),(111.30±20.45)U/L]were significantly lower than those in the ischemia-reperfusion group mice[(120.16±14.67),(202.45±18.74)U/L,t=9.492,10.390,P＜0.05].The levels of tumor necrosis factor a,interleukin-1 β,and interleukin-6 in the met-formin group mice[(67.94±8.16),(50.46±4.95),(75.06±6.63)pg/g]were lower than those in the sham operation group mice[(111.29±8.75),(93.37±10.79),(117.94±13.94)pg/g,t=11.460,11.420,8.782,P＜0.05].Transcriptome analysis showed that miR-19a was the most significantly differ-ent miRNA.The expression level of miR-19a in metformin group mice(0.78±0.09)was lower than that in sham surgery group mice liver tissue(0.95±0.13,t=5.992,P＜0.05).Bioinformatics studies showed that SIRT1 is the target gene of miR-19a.The expression level of SIRT1 protein in metformin group mice(0.98±0.10)was lower than that in sham surgery group mice liver tissue(1.56±0.12,t=11.680,P＜0.05).The acetylation level of NF kB p65 in metformin group mice(0.72±0.06)was high-er than that in sham surgery group mice liver tissue(0.35±0.08,t=11.480,P＜0.05).Conclusion Metformin regulates SIRT1 expression level through miR-19a,thereby affecting NF kB acetylation,inhibi-ting the release of inflammatory factors,and protecting against liver ischemia-reperfusion injury.
MetforminMicroRNA-19aLiver ischemia-reperfusion injurySilencing regula-tory protein 1Nuclear transcription factor
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