Effect of glucocorticoids on miRNA expression spectrum of rat femoral head microcirculation endothelial cells

The study profiled the differential miRNA expression from femoral head bone microvascular endothelial cells (BMECs) between model group and control group to explore the pathogenesis of steroid-induced osteonecrosis of femoral head (ONFH). Twenty 8-week-old Female Sprague-Dawley (SD) rats were randomly divided into control and model groups. Rats in model group received an intraperitoneal injection of 20-μg/kg lipopolysaccharide (LPS) at an interval of 24 h. Then, 24 h later, rats received three doses of 40-mg/kg methylprednisolone by intramuscular injection at intervals of 24 h. In control group, rats received the same volume of normal saline. After 4 weeks, the femoral heads were sectioned to confirm the establishment of the model. To replicate the animal model ex vivo, BMECs were isolated. Different miRNAs were screened using Agilent Gene Spring GX software, and real-time quantitative polymerase chain reaction (qPCR) was used to confirm the results of miRNA microarray analysis. The differentially expressed miRNA were assessed by bioinformatics analysis. Four differentially expressed miRNAs were identified (two upregulated: miR-132-3p, miR-335 and two down regulated: miR-466b-2-3p, let-7c-1-3p). qPCR results were consistent with the gene-chip results. Steroid-induced ONFH may cause miRNA changes in BMSCs. miR-132-3p and miR-335 may be important in steroid-induced ONFH.