Exercise enhance the ectopic bone formation of calcium phosphate biomaterials in muscles of mice

- Our study proves that calcium phosphate (Ca-P) biomaterial has good osteoinductivity.
- Our study indicates TRPV1−/− can reduce algesia and enhance the athletic ability in mice.
- Our study suggests patients with bone defects can promote healing through appropriate exercise.

ObjectiveTo investigate whether exercise can enhance ectopic bone formation of calcium phosphate (Ca-P) biomaterials in muscles of mice.MethodsFirstly, ten transient receptor potential vanilloid subfamily member 1 (TRPV1) knockout mice (group KO) and ten C57BL/6 mice (group WT) were randomly chosen, 10 μg Ca-P biomaterials were implanted into the thigh muscle pouch of each mouse which was far away from femur; after that, all animals were kept in open field for free exploration 5 min, and the movement time and distance were automatically analyzed. Ten weeks later, the Ca-P samples were harvested for histological staining and immunochemistry. Secondly, the Ca-P biomaterials were implanted into the thigh muscle pouch of C57BL/6 mice the same as previous operation, and then randomly divided into two groups: running group and non-running group (n = 10); in running group, all mice run 1 h as a speed of 6 m/h in a treadmill for 10 weeks. Ten weeks later, the blood was collected to detect the interleukin-4 (IL-4) and IL-12 levels by enzyme linked immunosorbent assay (ELISA), and the samples were harvested for histological staining.ResultsIn groups KO and WT, both the movement time and distance were significant higher in group KO than that in group WT (P < 0.05); furthermore, the histology staining results showed that lots of new bone and bone marrow tissues were observed in group KO, but only bone matrix-like substances were observed in group WT. In running group and non-running group, the ELISA results indicated that the immunological genes, both IL-4 and IL-12 levels were significant higher in running group than that in non-running group (P < 0.05); besides that, more new bone tissues were observed in running group than that in non-running group.ConclusionKnockout of TRPV1 in mice could reduce algesia and induce the stronger athletic ability of mice, causing better osteoinductivity of Ca-P biomaterials both in TRPV1−/− mice and running mice; according to this, we want to offer a proposal to patients who suffer from bone defects and artificial bone transplantation: do moderate exercise, don't convalesce all the time.