Amorphous Calcium Carbonate Enhances Fracture Healing in a Rat Fracture Model

Delayed and failed fracture repair and bone healing remains a significant public health issue. Dietary supplements serve as a safe, inexpensive, and non-surgical means to aid in different stages of fracture repair. Studies have shown that amorphous calcium carbonate (ACC) is absorbed 2 to 4.6 times higher than crystalline calcium carbonate in humans. In the present study, we assessed the efficacy of Density ACC supplement on femoral fracture healing in a male Wistar rat model. Fifty male Wistar rats were divided into five groups (n = 6 per group); Sham, Fracture + Water, Fracture + 0.5x (206 mg/kg) ACC, Fracture + 1x ACC (412 mg/kg) and Fracture + 1.5x (618 mg/kg) ACC to that of human supplement doses of ACC. A 21-gauze needle was placed in the left femoral shaft and waited three weeks. After three weeks, the sham group of rats was left without fracture, and the remaining animals were fractured with an impactor at the left mid-femur, followed by treatment with different doses of ACC for three weeks orally. Weight-bearing, microcomputed tomography, and serum biomarkers were evaluated weekly. After three weeks, the rats were sacrificed and femur bones were isolated for the evaluation of biomechanical strength and histological analysis. Weight-bearing test showed that treatment with ACC at all the tested doses led to a significant increase in weight-bearing compared to the controls. In addition, microcomputed- tomography and histological studies revealed that ACC treatment improved callus formation dose-dependently. Moreover, biomechanical strength was better in ACC-treated rats in a dose-dependent fashion than in the controls. In addition, supplementation with ACC significantly lowered the bone formation and resorption (BFR) marker levels 2-3 weeks post-fracture induction indicating accelerated fracture recovery. Our preliminary data demonstrate that ACC supplement improves fracture healing in a shorter time than the control rats.