The Expression Of MiR-140-3p/-5p In Synovial Fluid Of Knee Osteoarthritis

Objective The expression profile of mi R-140-3p and mi R-140-5p in synovial fluid(SF) of knee osteoarthritis(OA) were investigated and whether SF levels of mi R-140-3p and mi R-140-5p are correlated with different stage of knee OA patients were assessed, through which mean to provide some novel and specific marker for clinical diagnosis of knee OA.Methods All primary knee OA, gouty arthritis(GA) and rheumatoid arthritis(RA) gout patients were diagnosed with the criteria of American Rheumatism Association(ARA). Kellgren-Lawrence grading(KLG) was used to assess radiographic severity of knee OA and patients were stratified into mild(KLG<2), moderate(KLG=2) and severe(KLG>2) knee OA. The differential expression of mi R-140-3p/mi R-140-5p was further validated by SYBR Green quantitative PCR of individual samples. All data were processed using SPSS 13.0 software. Kolmogorov–Smirnov normality test(K-S test) was used to analyze the expression values of mi R-140-3p and-5p. when the expression values didn’t coincided with normal distribution, a log-transformed were used to create a normal distribution for parametric analysis. Then homogeneity of variance was analyzed using the Levene test. If the variances were homogeneous, the data were analyzed using one-way analysis of variance or using multiple comparison tests(least significant difference) for between-group comparisons. Otherwise, between-group comparisons were carried out using the Tamhane T2 test. Correlations between mi R-140-3p/mi R-140-5p expression and OA severity were estimated using Spearman correlation. Pearson correlation were used to examine relationships between mi R-140-3p/mi R-140-5p expression and age in different severity of OA. Alpha was set at 0.05.Results Synovial fluid(SF) samples were collected from 45 knee OA patients(15 mild, 15 moderate and 15 severe), 10 healthy volunteers, 10 gouty arthritis(GA) patients and 10 rheumatoid arthritis(RA) patients knee joints. Expression of mi R-140-3p/mi R-140-5p was down-regulated in OA SF, showing statistical difference between OA group and non-OA group, and increased OA severity was associated with a decreased expression of mi R-140-3p/mi R-140-5p. The expression quantity of mi R-140-3p in normal control group was 11.4 times higher than that in OA groups, and the expression quantity of mi R-140-5p in normal control group was 9.4 times higher than that in OA groups. The Spearman rank correlation analysis suggested that the expression of mi R-140-3p/-5p was negatively correlated with OA severity. In addition, there was difference in the expression of mi R-140-3p/-5p in the SF of the same case, and the expression of mi R-140-5p was 7.4 times than that of mi R-140-3p.Conclusion The expression of mi R-140-3p/-5p could be detected in SF of all subjects which were down-regulated in knee OA compared to non-OA cases, and the expression of mi R-140-3p/-5p were negatively correlated with OA severity. The dys-regulation of mi R-140-3p/-5p in SF and their correlations with different severity of OA might provide important theoretical basis for OA classfication and both maybe serve as some valuable biomarkers in diagnosis of OA.