LncRNA Neat1 Promotes Regeneration after Spinal Cord Injury by Targeting miR-29b.

Abstract

Previous studies have shown that lncRNA NEAT1 and miR-29b are closely associated with repair of the injured spinal cord. However, the mechanism by which lncRNA NEAT1 promotes regeneration after spinal cord injury by regulating miR-29b has not been reported. Toexplore this mechanism, we established a rat model of spinalcord injury(SCI). The experimental rats were randomly assigned to one of six groups:the sham,model, si-NEAT1, miR-29b, si-NEAT1 + negative control and si-NEAT1 + si-miR-29b groups. Thehind limb motor functionof the rats was evaluatedondays 1,3, 7, 14,and 21 aftermodellingusingtheBBBratingscale. Seven days after theoperation, attenuation of pathological changes ininjured spinal cord tissues wasevaluated by HE staining. Anteriorhornneuronsandcavitiesinthe injuredareawerecounted by Nissl staining. In addition, the TUNEL assay was employed to study neuronal apoptosis in the anterior horn, and the expression of the apoptotic proteins Bcl-2 and Bax was analysed by western blotting. Finally,the protein expression of GFAP,NCAM,GAP43, and SCG10 wasmeasured byimmunohistochemistryand western blotting. BBBscoresrevealedthat decreasing the level of NEAT1 improvedthehind limb motor function ofthe rats by increasing miR-29b expression. H&Eand Nissl staining showedthatsilencingNEAT1attenuatedlesions in thespinal cord anddecreasedthenumber of cavities inthe injured spinal cord by upregulatingmiR-29b. Immunohistochemistryandwesternblottingsuggestedthatsilencing NEAT1significantly downregulatedGFAP expressionand upregulatedGAP43, SCG10 andNCAM expression byinducing overexpression ofmiR-29b. The TUNEL assay and western blotting also showed that silencing NEAT1 attenuated neuronal apoptosis.