Significant Effect of Crocin on the Gene Expression of MicroRNA-21 and MicroRNA-155 in Patients with Osteoarthritis.

Osteoarthritis (OA) is the most common form of arthritis associated with gradual joint destruction. The current treatment aims to alleviate pain and inflammation and improve the quality of life. Crocin is an active ingredient in saffron, with anti-inflammatory properties. MicroRNAs are small, non-coding RNAs that regulate gene expression. We aimed to evaluate the effect of crocin on the gene expression of microRNA-146a, microRNA-155, microRNA-223, and microRNA-21 in OA patients and compare it with a placebo. This study was approved and registered in the Iranian Registry of Clinical Trials (2015021910507N2) and ClinicalTrials.gov identifier: NCT03375814. Forty OA patients were randomly divided into two equal groups, receiving either crocin or placebo. Peripheral blood samples were collected before and four months after the intervention. The pain was assessed using the visual analog scale, and laboratory tests included C-reactive protein and erythrocyte sedimentation rate. The expression levels of microRNA-146a, microRNA-155, microRNA-223, and microRNA-21 genes were evaluated by SYBR Green real-time PCR. The results showed that the gene expression levels of microRNA-21 and microRNA-155 in patients receiving crocin were significantly decreased and increased, respectively. No significant changes were observed in microRNA-146a and microRNA-223 gene expression levels. In conclusion, crocin's anti-inflammatory role might be partly attributed to its effects on the gene expression of microRNA-21 and microRNA-155.