Experimental research on the effect of microRNA-21 inhibitor on a rat model of intervertebral disc degeneration.

Intervertebral disc degeneration is associated with angiogenesis and is the primary cause of disc-associated disease. Several studies have indicated the importance of microRNA (miR)-21 in angiogenesis. Thus, the present study aimed to validate the role and underlying mechanisms of miR-21 in a rat model of intervertebral disc degeneration. A total of 60 specific-pathogen-free Sprague-Dawley rats were used for in vivo experiments. A rat model of intervertebral disc degeneration was established and miR-21 inhibitor (antagomiR-21) was administered. The vertebral pulp and annulus fibrosus were isolated for immunohistochemical analysis of hypoxia inducible factor (HIF)-1 alpha and vascular endothelial growth factor (VEGF) expression. Lumbar spine proteoglycan content was detected with the phloroglucinol method. Disc cell apoptosis was detected with terminal deoxynucleotidyl-transferase-mediated dUTP nick end labeling staining. It was revealed that antagomiR-21 treatment decreased the expression of HIF-1 alpha and VEGF in the vertebral pulp and annulus fibrosus. Furthermore, antagomiR-21 treatment increased proteoglycan content and inhibited cell apoptosis in lumbar spines from model rats with intervertebral disc degeneration. In conclusion, antagomiR-21 treatment exerted a protective role in a rat model of intervertebral disc degeneration, which may provide the basis for a potential therapeutic approach in the treatment of disc-associated diseases.