In vivo assessment of bone repair by an injectable nanocomposite scaffold for local co-delivery of autologous platelet-rich plasma and calcitonin in a rat model

Abstract

Background Gellan gum is obtained from the bacterium Sphingomonas elodea and is a polysaccharide with carboxylic acid functional groups. The goal of this project was to investigate the osteoinductive effect of local administration of calcitonin through an injectable scaffold of gellan gum containing salmon calcitonin loaded in silsesquioxane nanoparticles, hydroxyapatite, and platelets rich plasma. Methods The femur of rats was defected by creating a 2 x 5 mm(2) hole using an electric drill. The defect was filled with an injectable hydrogel scaffold composed of gellan gum enriched with salmon calcitonin loaded in silsesquioxane nanoparticles, hydroxyapatite, platelets rich plasma, and then the radiologic images were taken. Bone densitometry and the histologic studies were carried out by Hematoxylin & Eosin test. Biochemical analysis was done to measure the serum alkaline phosphatase (ALP), calcium, and calcitonin concentration. Results Healing of the bone defects and bone densitometry in the treated group by calcitonin-loaded scaffold was significantly higher (p < 0.05) and bone formation occupied 75 of the defect was greater than in other groups. Serum ALP and calcium levels in the scaffold-loaded calcitonin group were more than in the other groups (p < 0.05). The osteogenic marker genes also increased significantly (p < 0.05) with free calcitonin and the scaffold. Conclusions Gellan gum-based scaffold loaded with calcitonin may be considered a promising local treatment to progress bone formation in repairing skeletal injuries.