Magnesium lithospermate B inhibits titanium particles-induced osteoclast formation by c-fos and inhibiting NFATc1 expression.

Purpose: Titanium particle-induced osteolysis is one of the important causes of aseptic loosening of artificial joints. Previous studies have shown the potential of natural compounds in preventing Ti particle-induced bone resorption. In this study, we observed the effects of magnesium lithospermate B (MLB) on titanium particle-induced osteoclast activity in vitro. Materials and Methods: RAW264.7 cells were treated with titanium particles (0.1 mg/mL) in the presence or absence of MLB (200 nmol/L). We evaluated the osteoclast formation, bone pits formation and tartrate-resistant acid phosphatase 5b (Tracp5b) levels. Reverse transcription polymerase chain reaction (RT-PCR) and Western blot were used to evaluate osteoclast differentiation-related genes (TRAF6, NFATc1, and c-fos) and protein expression. Results: The number of osteoclasts, pit formation and Tracp5b levels were all the group treated with titanium particles compared to the control group (all p < 0.05). Titanium particles also promoted the expression of the TRAF6, NFATc1 and c-fos genes and protein expression. MLB significantly abolished the titanium particle-enhanced osteoclast and pits formation, and Traf6, NFATc1, and c-fos expression. Conclusions: Our data demonstrated that MLB can suppress titanium-induced osteoclast activity via inhibiting c-fos and NFATc1 expression.

[Repair of forefoot skin and soft tissue defect with reverse lateral tarsal artery flap].

OBJECTIVE: To investigate the operative procedure and the clinical results of reverse lateral tarsal artery flap in treating forefoot skin and soft tissue defect. METHODS: From August 2007 to April 2009, 11 patients with forefoot skin and soft tissue defect were treated with reverse lateral tarsal artery flaps, including 7 males and 4 females aged from 16 to 60 years (36 years on average). Of 11 cases, defects were caused by crash in 5 cases, by grind contusion in 3 cases and the course disease was 4-12 hours; by tumor extended resection in 3 cases and the disease course was 3-12 months. There were 5 wounds on the dorsum of first metatarsophalangeal joint, 2 on the dorsum of the first toes, and 4 on the dorsum of distal part of metatarsal bones. The area of defect ranged from 4 cm x 2 cm to 6 cm x 5 cm. There were 6 cases of tendon exposure, 4 cases of tendon defect with bone exposure, and 1 case of tendon defect with open dislocation of metatarsophalangeal joint. The flap was designed with dorsal artery of foot as its pedicle. The plantar perforating branch was designed as its rotating point. And the flaps were transferred retrogradely to repair the forefoot wounds. The flap area ranged from 4.5 cm x 2.5 cm to 6.5 cm x 4.5 cm. The lateral dorsal nerve of foot was anastomosed with the nerve in wound area in 7 cases. Donor site was covered by full thickness skin graft. RESULTS: Partial necrosis occurred and was cured by dressing change, followed by skin graft in 2 cases. The flaps survived and primary healing was achieved in the other 9 cases. All the skin grafts of donor site survived and primary healing was achieved after operation. All the patients were followed up for 6 months to 2 years, averaged 13 months. The texture and color of the flap were similar to skin at the recipient site. All patients returned to normal in walking and running and no ulceration occurred. The two point discrimination was 5-12 mm 6 months after operation in 7 patients who received nerve anastomosis, while only protective sensation recovered partly in the other 4 patients whose cutaneous nerve were not anastomosed. CONCLUSION: Reverse lateral tarsal artery flap has the perfect shape and its blood vessel is constant. The blood pedicle is thick and long enough when transferred retrogradely. The flap is a good choice in the treatment of forefoot skin and soft tissue defect.

[Comparison of effects of flap delay and vascular endothelial growth factor on the viability of the rat dorsal flap].

OBJECTIVE: To compare the effects of flap delay and vascular endothelial growth factor (VEGF) on the viability of the rat dorsal flap. METHODS: Thirty rats were divided into 3 groups: saline group, flap delay group and VEGF group. The rats in flap delay group underwent flap delay by keeping bipedicle untouched, and the cranial pedicle was cut 7 days later. The rats in VEGF group were given VEGF solution locally when the flaps were elevated in the operation. The rats in saline group were given saline solution in the same way. Five days after the single pedicle flaps were performed, the flap survival rate was measured. The flap tissues were collected to measure and analyze the microvascular density, diameter and sectional area by immunochemical method. RESULTS: The flap survival rate of flap delay group was similar to that of VEGF group and there is no statistically significant difference (P>0.05). The vascular diameter of flap delay group was much larger than that of saline group and VEGF group, showing statistically significant difference (P<0.05). The vascular density of VEGF group was much higher than that of saline group and flap delay group, showing statistically significant difference (P<0.05). The vascular sectional area of flap delay group was similar to that of VEGF group (P>0.05). CONCLUSION: The change in the flap after flap delay is manifested as obvious dilatation of microvessels, while the change in the flap after the injection of VEGF is manifested as obvious vascular proliferation. Both flap delay and VEGF can increase the vascular sectional area and the viability of the flap, but the mechanism is different.