LAUSR

OBJECTIVE To investigate the effect of microRNA-210 on the spinal cord injury (SCI) and its underlying mechanism. MATERIALS AND METHODS The mouse SCI model was established. Mice were randomly assigned into 4 groups, namely the sham operation group (sham group), surgery group (SCI group), surgery+NC group (SCI+NC group) and surgery+microRNA-210 overexpression group (SCI+microRNA-210 mimics group). The mRNA levels of microRNA-210 and the key genes in the JAK-STAT pathway of the four groups were detected by Real-Time Polymerase Chain Reaction (RT-PCR) at different time points. Protein levels of JAK2 and STAT3 in mice of the four groups were detected by Western blot. To investigate the role of microRNA-210 in SCI recovery, changes in the motor function of mice were detected. RESULTS Grip strengths of right and left forelimbs in mice from the sham group were temporarily decreased at the early stage after surgery, which were gradually recovered to the preoperative levels on the 3rd postoperative day. However, mice in SCI group were unable to complete the grip strength determination at the early stage after surgery. Mice in SCI group were capable of grasping on the 7th postoperative day. Besides, grip strengths of mice in SCI group were remarkably lower than those of sham group until the end-point (on the 50th day). Furthermore, mRNA levels of microRNA-210 in mice of SCI group were decreased in a time-dependent manner (p<0.05). Higher grip strengths were observed in mice of SCI+microRNA-210 mimics group in comparison with those of SCI group and SCI+NC group (p<0.05). In addition, Western blot showed that protein levels of JAK2 and STAT3 in mice of SCI group were increased in a time-dependent manner (p<0.05). Moreover, protein levels of JAK2, STAT3, and MCP-1 in mice of SCI+NC group were remarkably higher than those in the sham group and SCI+microRNA-210 mimics group (p<0.05). CONCLUSIONS MicroRNA-210 is down-regulated in SCI mice. Grip strengths of SCI mice can be recovered after microRNA-210 overexpression via inhibiting inflammatory response by the JAK-STAT pathway.