Expression Of MicroRNA-223 In Injuried Spinal Cord Of Rats And Its Correlation With RhoB

Objective To investigate and analyse the expression of microRNA-223 in injuried spinal cord of rats and its correlation with RhoB, and provide theoretical basis for exploring therapeutic targets of spinal cord injury. Methods The acute spinal cord injury model was built using modified Allen methods. 108 adult SD rats were assigned randomly to blank control group(group A) and SCI groups(group B). Rats in SCI groups were divided into 6h,12 h,24h,3d and 7d group after injury. Neurologic function score of hind limb(BBB score) was observed after operation. The expression and location of miRNA-223 and RhoB gene were detected using real time RT-PCR; the spatial relationship of the expressions of miRNA-223 and RhoB in spinal cord injury tissue. Results 1 BBB score: Compared with group A,the BBB score of group B was significantly lower(P<0.05). 2 HE staining: The spinal cord structure in group A is normal,while the spinal cord in group B were obviously injuried.Extensive neuronal edema appears at 6 hours after SCI.The primary pathological change in the period of 12 hours to 24 hours after SCI is neuronal necrosis and acute inflammatory reaction; and increased vascular permeability and abundant inflammatory-cell infiltrate can be observed in the period of 24 hours to 7 days after SCI. 3 Real-time PCR: Compared with group A, the relative expression of miRNA-223 in group B is significantly higher, The relative expression of RhoB in group B was increased after SCI,and reach the peak at 24 hours after SCI, then decreased there after. The expression of RhoB in group Bat 7days after SCI in still significantly higher than that of the blank control samples(set at 1.000, P<0.05). There was a positive correlation between the expression of miRNA-223 and RhoB in injuried spinal cord of rat(r=0.89,P<0.05). 4 In Situ Hybridization(ISH): mi RNA-223 mainly expressed in ventral horn motor neurons in the period of 6、12、24hours after spinal cord injury.Rho B m RNAs mainly expressed in the period of 6 hours to 3 days after spinal cord injury, also in ventral horn motor neurons. Conclusion The expression of mi RNA-223 gene is significantly increased after spinal cord injury.There is a positive correlation between the expression of mi RNA-223 and Rho B after SCI. The expression of Rho B may be regulated by mi RNA-223.