【Animal Modeling】-A weekly subcutaneous injection of rhPTH(1-34) promotes fracture healing in rats

  Objective: To observe the effect of weekly subcutaneous injection of parathyroid hormone rhPTH (1-34) on fracture healing in rats.

  Methods: Fifty 3-month-old male SD rats with left tibia fractures were randomly divided into 5 groups (n=10/group) according to the dose and frequency of subcutaneous injection of rhPTH (1-34) after internal fixation with Kirschner wire. : weekly 10, 20 μg/kg group; daily 10, 20 μg/kg group; weekly subcutaneous injection of the same amount (500 μL) of normal saline as control group. After 4 weeks of treatment, the specimens were sacrificed, and the fracture healing was detected by small animal X-ray, dual-energy X-ray, micro-CT and three-point bending biomechanical experiment.

  Results: No matter weekly or daily subcutaneous injection of rhPTH(1-34), the bone mineral density was higher than that of the control group (P<0.05). The fracture healing effect of the weekly 20 μg/kg group was better than that of the control group. ) The 20 μg/kg weekly group was 26.2% and 51.4% higher than the control group in terms of bone mineral density, mineralized callus volume, total callus volume, percentage of mineralized callus volume in total callus volume, and maximum load, respectively. , 21.6%, 24.5%, 29.3%. The maximum load of 20 μg/kg per week, 10 μg/kg per day and 20 μg/kg per day was higher than that in the control group (P<0.01); 10="" 20="" per="" week="" p="">0.05).

  Conclusion: Weekly subcutaneous injection of parathyroid hormone (rhPTH1-34) (10, 20 μg/kg) can promote fracture healing, but the same single dose, the effect of daily subcutaneous injection is still better than weekly subcutaneous effect.