Fig. 3

a Diagram of relative miRNA expression levels by qRT-PCR in the serum of healthy individuals (n = 12) and OA patients (n = 12). MiR-25-1 was used for normalization of the real-time PCR data. *p < 0.05 as measured using an unpaired Students’s t test. Hsa-miR-140-3p, hsa-miR-671-3p, and hsa-miR-33b-3p were significantly downregulated in serum samples of OA patients compared to healthy individuals. b Comparative diagram of miRNA expression levels between miRNA microarray analysis and as validated by qRT-PCR in serum samples of OA patients (n = 12) and healthy individuals (n = 12). The expression levels of hsa-miR-33b-3p and hsa-miR-4284 coincided between the two methodologies, while hsa-miR-1233-3p, hsa-miR-140-3p, hsa-miR-150-5p, hsa-miR-663a, and hsa-miR-671-3p were marginally overexpressed in microarray analysis and appeared to be down-regulated with qRT-PCR