Lipopolysaccharide (LPS)-induced mouse calvarial bone erosion model

We constructed a LPS-stimulated bone destruction model in mouse calvaria based on our previous study ¹⁰. Healthy (age, 6-8 weeks) C57/BL6 mice were randomly divided into five groups (n = 6): (1) PBS control, (2) LPS, (3) LPS+ISL, (4) LPS+MSNs, and (5) LPS+MSNs-ISL. Under mild anesthesia, mice were subcutaneously injected with PBS or LPS (10 mg/kg body weight) at the midline of the calvarial sagittal suture for 7 days each. Then, the corresponding groups of mice were subcutaneously injected with (1) PBS, (2) PBS, (3) ISL (3.125 mg/kg body weight), (4) MSNs (50 mg/kg body weight), and (5) MSNs-ISL (50 mg/kg body weight) at 1 day before LPS injection and 30 min prior to the daily injection of LPS once in every 2 days. In the in vivo experiments, the ISL concentration was similar to that of ISL-encapsulated in the MSNs-ISL group, which was determined according to the procedure for calculating the loading and release efficacies. Following the final LPS injection, mice were sacrificed, and their calvaria was collected and fixed in 4% paraformaldehyde for 2 days.