Figure 3 MiR-7 was upregulated in OA and directly targeted KLF4. (A) qRT-PCR showing miR-346, miR-15a, miR-103a, miR-29a, miR-7, miR-18a, miR-135b, miR-140, and miR-135a expression in IL-1β-stimulated chondrocytes. (B) MiR-7 expression in human OA and normal cartilage tissues as shown by qRT-PCR. (C) The expression levels of MMP3, ADAMTS5, COL2A1, and Aggrecan in OA model cartilage tissues injected with miR-7 inhibitor as shown by qRT-PCR. (D) Safranin-O and fast green staining showing the morphology changes of OA model cartilage tissues. Bar: 500 μm. (E) Luciferase activity assay revealed the target relationship between miR-7 and KLF4. (F, G) Western blot results showing KLF4 expression in OA chondrocytes transfected by miR-7 mimics. * p<0.05; ** p<0.01, *** p<0.001; **** p<0.0001.