Niacin treatment prevents bone loss in iron overload osteoporotic rats via activation of SIRT1 signaling pathway.

Recently, more and more studies have revealed that iron overload can lead to osteoporosis by inducing oxidative stress. Niacin (NAN), also known as nicotinate or vitamin B3, has been confirmed to possess potent antioxidative effects. In addition, very little is currently known about the protective effects of NAN on iron overload in osteoporotic bone tissue. Therefore, we aimed to evaluate the protective effect of niacin on iron overload-induced bone injury and to investigate the effect and underlying mechanisms of the niacin and iron overload on intracellular antioxidant properties. When MC3T3-E1 and RAW264.7 cells were cultured in the presence of ammonium ferric citrate(FAC), NAN therapy could increase the matrix mineralization and promote expression of osteogenic markers in MC3T3-E1, inhibit osteoclastic differentiation of RAW264.7 cells, while increasing intracellular reactive oxygen species (ROS) levels and strengthening mitochondrial membrane potential (MMP). In the ovariectomized (OVX) rat model, NAN had an obvious protective effect against iron-overloaded injury. Meanwhile, superoxide dismutase 2 (SOD2), intracellular antioxidant enzymes and silent information regulator type 1 (SIRT1), were up-regulated in response to NAN exposures in MC3T3-E1. Furthermore, SIRT1 inhibitor EX527 attenuated the protective effects of NAN. Results revealed that NAN could stimulate osteogenic differentiation, inhibit osteoclastic differentiation and markedly increased antioxidant properties in cells through the induction of SIRT1. Studies suggest that niacin is a promising agent for preventing bone loss in iron overload conditions.

[Minimally invasive percutaneous plate internal fixation through anterolateral single incision for the treatment of open distal tibiofibula fractures].

OBJECTIVE: To investigate therapeutic effect of minimally invasive percutaneous plate internal fixation (MIPPO) through a single incision in treating open distal tibiofibula fractures. METHODS: From March 2015 to February 2019, 10 patients with open distal tibiofibula fractures were treated with MIPPO technique through single anterolateral incision, including 8 males and 2 females, aged from 31 to 68 years old. According to Gustilo classification, 6 patients were typeⅠ, 3 patients were typeⅡand 1 patient was type ⅢA. Operative time, intraoperative blood loss and fracture healing were observed, Mazur ankle joint scoring was used to evaluate clinical effect. RESULTS: All patients were followed up from 9 to 24 months. Operative time ranged from 85 to 120 min, intraoperative blood loss ranged from 80 to 200 ml, fracture healing time ranged from 18 to 30 weeks. Nine patients with Gustilo typeⅠandⅡachieved satisfactory healing wound, original wound of 1 patient with Gustilo type ⅢA was poor, and healed by skin flap transplantation at stageⅡ. No steel exposed and infection occurred. According to Mazur ankle scoring at the final following-up, total score was from 61 to 97, and 8 patients got excellent result, 1 good and 1 poor. CONCLUSION: MIPPO technique through anterolateral single incision for the treatment of open distal tibiofibula fractures could protect original medial wound in opertaion, avoid plate exposed through anterolateral extensor tendon to cover internal fixation, and MIPPO technique could protect fracture end blood flow to improve fracture healing rate, and it is a kind of choice.