MiR-25-3p Induces Repairment Of Rat Dorsal Column Lesion After Sciatic Nerve Conditioning Injury

Objective To study the effect of sciatic nerve conditioning injury in repairment of dorsal column lesion and its potential mechanism.Method 1. To observe the morphological change of dorsal column 21 d post dorsal column lesion,HE staining and immunohistochemical staining were used. 2. Using microarray 3.0 gene chips to detective microRNA expression of dorsal root ganglion of Pretreatment Group and Lesion Group in 1d, 7d, 14 d and 28 d post dorsal column lesion. Bioinformatics were used to investigate the differential expression of microRNAs. To validate the result, RT-q PCR were applied. 3. Targetscan was used to predictive the target m RNA of the microRNA which was screened out by bioinformatics. And western blot and PCR were used to detect expression of the mRNA.Result 1. Comparing with the Lesion Group, the shape of nerve fiber bundle was more regular in caudal lesion site of Pretreatment Group in 21 d post dorsal column lesion. 2. 21 days post dorsal column lesion, comparing with the Lesion Group, the expression level of neurofilament-200(NF200) was significantly increased in caudal lesion site of Pretreatment Group. The IOD of NF200 of Pretreatment Group was higher than Lesion Group. 3. To compare with control group, miR-25-3p expression of Pretreatment Group was upregulated in 1d, 7d and 14 d post dorsal column lesion. Using clustering analysis to analyze the expression of miR-25-3p, found that 7d of Pretreatment Group can be a separate group. 4. To validate the microarray result, RT-q PCR were applied. The result of PCR shows good consistency with the results of the microarray chip. 5. To detect expression of PTEN western blot was used. PTEN protein expression of Pretreatment Group in 1d, 7d and 14 d post dorsal column lesion were lower than control group, and there was no statistical difference between Lesion Group and control group. There was no statistical difference between PTEN m RNA expression of Pretreatment Group, Lesion Group and control group.Conclusion 1. Sciatic nerve conditioning injury can promote repairmen of dorsal column after spinal cord injury. 2. Mi R-25-3p expression of Pretreatment Group was upregulated in 1d, 7d and 14 d post dorsal column lesion. 3. PTEN protein expression of Pretreatment Group in 1d, 7d and 14 d post dorsal column lesion were lower than control group. 4. Mi R-25-3p is the key microRNA in the biological process, sciatic nerve conditioning injury promote the repairment of dorsal column after spinal cord injury, its effect may be related to expression of PTEN.