2022, Vol. 26 ›› Issue (29): 4658-4665

MicroRNA-20b-5p effects on cartilage and subchondral bone angiogenesis in early-stage osteoarthritis rats

Lu Qigui1, Xie Pingjin1, Luo Zhen2, 3, Li Feilong2, Chen Qunqun2, Chai Shengting2   

Abstract: BACKGROUND: Angiogenesis is an important pathological feature of early-stage knee osteoarthritis. Intra-articular injection of microRNA for the inhibition of angiogenesis may provide a new target for the treatment of early-stage knee osteoarthritis.
OBJECTIVE: To observe the effect of microRNA-20b-5p (miR-20b-5p) agomir on the angiogenesis of articular cartilage and subchondral bone in rats with early-stage knee osteoarthritis, and to explore the possible protective mechanism of miR-20b-5p.
METHODS: Twelve male Sprague-Dawley rats were enrolled, three of which were randomly selected as blank group, and the remaining nine rats were randomly divided into model group, miR-20b agomir group and miR-20b agomir NC group, with three rats in each group. One week after modeling, the blank group was not treated, while in the model, miR-20b agomir and miR-20b agomir NC groups, 0.2 mL of normal saline, miR-20b-5p agomir saline solution and miR-20b-5p agomir NC saline solution was injected into the rat bilateral knee joints, respectively. Four weeks later, the rats in each group were killed and the knee joints were taken for saffron O-fast green staining, immunohistochemical staining, and Osteoarthritis Research Society International scoring. Real-time fluorescence quantitative PCR and western blot assay were used to detect the expression of hypoxia inducible factor 1α and vascular endothelial growth factor at mRNA and protein levels in the cartilage and subchondral bone.
RESULTS AND CONCLUSION: The score of Osteoarthritis Research Society International in the miR-20b agomir group was significantly lower than that in the model group and miR-20b agomir NC group (P < 0.05), but there was no significant difference between model group and miR-20b agomir NC group (P > 0.05). The pathological sections of the knee joint showed that there was an increase in the loss of cartilage matrix and the expression of hypoxia inducible factor-1α and vascular endothelial growth factor proteins in the cartilage and subchondral bone in all intervention groups compared with the blank group. The degree of cartilage matrix loss and the expression of hypoxia inducible factor 1α and vascular endothelial growth factor proteins in the cartilage and subchondral bone in the miR-20b agomir group were lower than those in the model group and miR-20b agomir NC group. The mRNA and protein expression levels of hypoxia inducible factor 1α and vascular endothelial growth factor in the cartilage and subchondral bone in the miR-20b agomir group were significantly lower than those in the model group and miR-20b agomir NC group (P < 0.05). To conclude, overexpression of miR-20b-5p can protect early-stage osteoarthritis cartilage and subchondral bone by inhibiting angiogenesis mediated by the hypoxia-inducible factor 1α/vascular endothelial growth factor pathway.
Key words: early-stage knee osteoarthritis, microRNA-20b-5p, hypoxia-inducible factor 1α, vascular endothelial growth factor, angiogenesis