Role of miR-199a-5p in osteoblast differentiation by targeting TET2.

OBJECTIVE: miR-199a-5p was increased during osteoblast differentiation, which may target and regulate TET2, a gene attracted a lot of attention in the osteoblast differentiation in the past few years. However, the role of miR-199a-5p in osteoblast differentiation by targeting TET2 is not established. METHODS: The correlation between miR-199a-5p and TET2 was verified through dual luciferase reporter assay, and their expressions in human bone marrow stromal cells (hBMSCs) during the osteoblast differentiation were detected. hBMSCs were transfected with TET2 siRNA, miR-199a-5p mimic or/and TET2 CRISPR activation plasmid., and then prepared for the induction of osteoblast differentiation, followed by alkaline phosphatase (ALP) and alizarin red staining, qRT-PCR and Western blotting. In vivo, ovariectomized (OVX) mice were injected with agomir-miR-199a-5p, antagomiR-199a-5p or/and TET2 siRNA to calculate the BMD and BV/TV ratio of mice, as well as to measure the expressions of osteogenesis-related genes in bone tissues. RESULTS: A gradual increase of miR-199a-5p was observed in hBMSCs during the induction of osteoblast differentiation, while TET2 expression was decreased. Besides, miR-199a-5p was reduced in the bone tissue of OVX mice, while TET2 was up-regulated. In addition, overexpression of miR-199a-5p and inhibition of TET2 augmented ALP activity in hBMSCs, with the enhanced calcification and the up-regulated expressions of Runx2, OSX and OCN, which also increased the quality of bone in OVX mice accompanying the enhancement BV/TV ratio, BMD and osteogenesis-related genes. CONCLUSION: MiR-199a-5p may promote the osteoblast differentiation and prevent OVX-induced osteoporosis by targeting TET2.

Effects of sealing the intramedullary femoral canal in total knee arthroplasty: A randomized study.

BACKGROUND: This study investigates the clinical effects of sealing the femoral canal by intramedullary alignment instrumentation in total knee arthroplasty (TKA). METHODS: One hundred twenty consecutive patients with knee osteoarthritis, who underwent unilateral TKA, were enrolled in the study and equally randomized into 2 groups: the sealing group and the control group. In the sealing group, the femoral canal was sealed with autogenous bone and cement using intramedullary alignment instrumentation, while the femoral hole was left open for patients in the control group. Blood loss, hemoglobin (Hb) reduction, and other parameters were recorded, as well as the duration of hospital stay and complications. The Hospital for Special Surgery (HSS) knee score was used to assess knee function at the final follow-up appointment. RESULTS: The calculated blood loss, hidden blood loss, transfusion requirements, drainage volume, and Hb reduction measurements were significantly different (P < .05) between the 2 groups. There were no significant differences in the surgery time, intraoperative blood loss, length of hospital stay, HSS score or complications between the 2 groups (P > .05). CONCLUSIONS: Sealing the intramedullary canal with autologous bone and a cement plug is an effective method for reducing blood loss and decreasing blood transfusion requirements during TKA procedures that have increasing complication rates.