Expression of cyclooxygenase-2 is correlated with lncRNA-COX-2 in cirrhotic mice induced by carbon tetrachloride.

Multiple long non-coding RNAs (lncRNAs) have been demonstrated to be involved in liver disease. Increased cyclooxygenase-2 (COX‑2) levels have also been reported to be involved in the progression of liver cirrhosis. In the present study, the correlations between lncRNA‑COX‑2 RNA expression levels, COX‑2 mRNA expression levels and liver fibrosis were examined. Liver fibrosis was induced by intraperitoneal injection of carbon tetrachloride (CCl4) in mice for 2 months (CCl4‑2M) or 3 months (CCl4‑3M). Liver histopathological evaluation was conducted using hematoxylin and eosin and Masson trichrome staining. Hepatic expression of COX‑2 and lncRNA‑COX‑2 was evaluated by reverse transcription‑quantitative polymerase chain reaction and immunohistochemical staining. Compared with the control group, fibrotic areas were increased four and nine times in the CCl4‑2M group and the CCl4‑3M group, respectively. LncRNA-COX-2 and COX‑2 upregulation were observed in the cirrhotic liver. COX‑2 mRNA expression levels and lncRNA-COX-2 RNA expression levels were significantly positively correlated with the fibrotic area. In addition, COX‑2 mRNA expression was significantly positively correlated with lncRNA‑COX‑2 expression. These results suggest that expression of COX‑2 and lncRNA‑COX‑2 increased with the progression of liver fibrosis. LncRNA-COX-2 may potentially be considered as a novel therapeutic target for liver fibrosis.