Detection of the expression level of miR-140 using realtime fluorescent quantitative PCR in knee synovial fluid of osteoarthritis patients

Abstract

To examine the expression of microRNA-140 (miR-140) in osteoarthritis (OA) graded by X-ray diagnosis criteria of Kellgren and Lawrence and to provide a theoretical basis for further studing the role of miR-140 in OA development. Knee synovial fluid specimens were collected in 40 OA patients (the OA group), the OA group was divided into 4 subgroups according to X-ray diagnosis criteria of Kellgren and Lawrence: gradeIsubgroup (n=10), gradeII subgroup (n=10), gradeIII subgroup (n=10), and grade IV subgroup(n=10). Twenty patients served as a control group (the control group), including meniscus injury, cruciate ligament injury, trauma patients. The expression level of miR-140 in the knee synovial fluid was detected by real-time fluorescent quantitative polymerase chain reaction (stem-loop RT-qPCR, TaqMan). U6 snRNA was used as the reference control, and Ct value was calculated. MiR-140 was detected in all knee synovial fluid specimens. The expression level of miR-140 in the OA group was much lower than that in the control groupb (P<0.05). There was significant difference in the expression level of miR-140 between the grade IV subgroup and the gradeI, gradeII and gradeIII subgroups (all P<0.05). The expression levels of miR-140 was negatively related to the severity of OA (r=-0.917, P<0.05). MiR-140 in human knee synovial fluid can be detected conveniently by real-time PCR. The expression level of miR-140 decreases in the knee synovial fluid in OA patients, and is negatively related to the severity of OA. This may be related to the occurrence and development of OA, and can provide early potential diagnostic molecular target.