Objective To investigate whether microRNA (miRNA)-144 inhibitor can attenuate the injury of esophageal mucosa in rats with reflux esophagitis (RE) and its possible mechanism.Methods Eighteen male SD rats were randomly divided into sham group,RE group,and miRNA-144 inhibitor group,with 6 rats in each group.Rats in the RE group and miRNA-144 inhibitor group were recruited to establish RE animal models by tying the proximal stomach and constricting proximal pylorus.Rats in the miRNA-144 inhibitor group were administered with miRNA-144 antagomir to inhibit the expression of miRNA-144 in vivo by tail vein injection.The efficacy of miRNA-144 inhibitor and the mRNA expression of Toll-like receptor 4(TLR4),nuclear factor κB (NF-κB) and inhibitor of nuclear factor κB α(IκBα) in esophageal tissues in each group were detected by quantitative polymerase chain reaction (qPCR).The contents of interleukin (IL)-6,IL-8 and tumor necrosis factor α(TNF-α) in rat esophageal tissues were determined by enzyme-linked immunosorbent assay (ELISA).The protein expression of claudin 3(CLDN3) was detected by Western blotting,the protein expression of cleaved cysteine aspartic acid specific protease (caspase 3) and Ki-67 was detected by immunohistochemistry staining,and the apoptosis of esophageal mucosal cells was examined by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) assay.Results Compared with the sham group,the mRNA expression levels of TLR4,NF-κB and IκBα in esophageal tissues of rats in the RE group were significantly increased (P< 0.05,P<0.01),the contents of inflammatory factors (IL-6,IL-8 and TNF-α) and the expression of cleaved caspase 3(an apoptosis-related protein) were significantly increased (all P<0.05 in the former ones and P<0.01 in the latter one),the apoptosis of esophageal mucosal cells was increased (P<0.01),and the expression of CLDN3 protein (an index of esophageal mucosal barrier) was decreased (P<0.01).Compared with the RE group,inhibition of miRNA-144 significantly reduced the mRNA expression levels of TLR4,NF-κB and IκBα(all P<0.05) and the contents of inflammatory factors (IL-6,IL-8 and TNF-α)(all P<0.05),and then inhibited the apoptosis of mucosal cells in the esophagus of the RE rats (P<0.05) and elevated the expression of CLDN3 protein (P<0.01).Whereas,there was no impact on the proliferation of esophageal mucosal cells by inhibiting the expression of miRNA-144,and there was no significant difference in the number of Ki-67 positive cells between the miRNA-144 inhibitor group and RE group (P>0.05).Conclusion miRNA-144 inhibitor can attenuate the injury of esophageal mucosa in RE rats,and the effect may be mainly through TLR4/NF-κB signal pathway.