Effect of vitamin K1 on the healing process of osteoporotic fracture in aged rats and its mechanism
Xiaofeng Xue, FASEB J 2021 35(S1) 05289
To investigate the effect of vitamin K1 on the healing process of osteoporotic fracture and its mechanism by measuring interleukin- 6(IL-6), bone gla protein (BGP) and alkaline phosphatase (ALP) in animal serum.
Methods
64 Sprague-Dawley male aged osteoporosis rats (body weight 560±20g, age 20 months) were enrolled. The left femoral fracture model was made in rats and intramedullary fixation was performed with a 1.5mm diameter Kirschner wire. They were randomly divided into two groups: vitamin K1 injection group (32 rats) and control group (32 rats). The vitamin K1 group was intraperitoneally injected with vitamin K115mg/kg/3d after surgery, and the control group was intraperitoneally injected with 0.9% sodium chloride injection of the same volume for 8w. At 2w, 4w, 8w and 12w after fracture, 8 rats in the vitamin K1 injection group and 8 rats in the control group were randomly selected, and venous blood was collected. The levels of IL-6 and BGP in serum were detected by radioimmunology. The contents of calcium, phosphorus and ALP in serum were determined by spectrophotometry. Bone callus was taken for hematoxylin-eosin (HE) staining. Bone mineral density (BMD) of bone callus and right femur were measured at 2w, 4w, 8w and 12w. Radiological observation (X-ray) was performed at 12W.
Results
The serum IL-6 of vitamin K1 injection group was lower than that of control group at each time point, but the serum BGP, ALP, calcium and phosphorus product and BMD were higher than that of control group (P<0.05). The results of HE staining showed that chondrogenesis and endochondral osteogenesis were earlier in the vitamin K1 group than in the control group. X-ray films showed that the fracture line of vitamin K1 group was blurred 12 days after surgery, the bone callus connected the broken end, and the medullary cavity was recanalized. In the control group, the fracture line was still relatively clear 12 weeks after operation, and the callus connection at the broken end was not close.
Conclusion
Vitamin K1 can reduce the serum IL-6 content, increase the BGP, ALP content and the product of calcium and phosphorus, and then promote the healing of osteoporotic fracture in aged rats. Vitamin K1 can promote fracture healing, accelerated cartilage osteogenesis, accelerated mineralization, bone callus and whole body bone density increase.