miR-10a-5p, miR-99a-5p and miR-21-5p are steroid-responsive circulating microRNAs.

Steroid-induced osteonecrosis of the femoral head (ONFH) is a common orthopedic disease. The lack of specific manifestations and effective diagnostic methods make it difficult for this disease to be diagnosed at early stages. Recent studies have shown that microRNAs (miRNA) participate in the development of steroid-induced ONFH, but there is limited research into the diagnostic use of circulating miRNAs. Blood samples from 23 human subjects (7 systemic lupus erythematosus (SLE) patients with steroid-induced ONFH; 7 SLE controls without ONFH; and 9 healthy controls) and 71 rats (19 with steroid-induced ONFH; 28 receiving steroids without ONFH; and 24 untreated controls) were collected to verify the abundance of changes of 6 previously identified ONFH-associated plasma miRNAs (miR-423-5p, miR-99a-5p, miR-10a-5p, miR-21-5p, miR-130a-3p and miR-6787-5p) by quantitative RT-PCR (Reverse Transcription-Polymerase Chain Reaction). In humans, the circulating levels of miR-10a-5p, miR-99a-5p and miR-21-5p were increased in SLE patients treated with cortico steroid regardless of ONFH status when compared with healthy controls. However, miR-423-5p, miR-6787-5p and miR-130a-3p showed no significant differences between the three groups. In the rat model, the success rate of steroid-induced ONFH was 40.4% (19/47) based on pathological examination and confirmation by micro-CT scan. Similar to human plasma, the circulating levels of miR-10a-5p, miR-99a-5p and miR-21-5p were increased in steroid-treated rats independent of ONFH development. The serum levels of miR-10a-5p, miR-99a-5p and miR-21-5p were increased by steroid treatment regardless of ONFH development in both humans and rats. These data suggested that miR-10a-5p, miR-99a-5p and miR-21-5p are steroid-responsive circulating miRNAs, but they are not specific for diagnosing steroid-induced ONFH.