Abstract: Objective: To explore whether the gelatin microspheres sustained release CGRP and SP can promote bone formation in tooth socket of mice. Methods: The gelatin microspheres containing 10^-6 mol/L SP and CGRP were prepared and filled into the sockets of maxillary first molar on one side of 27 adult KM mice. The mice were divided into three groups, including SP, CGRP, and SP/CGRP mix groups randomly. 4 weeks later, the mice were sacrificed and the maxillae bone was harvested. The samples were embedded in methylmethacrylate for histological morphology examination. Results: The average BV/TV values were (30.25±0.92)% in experimental socket and (10.66±0.83)% in control socket (P＜0.05)in SP group;(19.46±1.46)% in experimental socket and (8.78±1.03)% in control socket(P＜0.05)in CGRP group:(59.45±3.07)% in experimental socket and (10.06±3.25)% in control socket(P＜0.05)in SP/CGRP mix group. Bone volume/tissue volume (BV/TV) was (59.453±3.071)% in the mixed experimental group and (10.062±3.254)% in the mixed blank group (P<0.05). Trabecular thicknesses (Tb.Th) were (0.076±0.009) % in the mixed blank group and 0.132±0.043 % in the mixed treatment group (P<0.05). Trabecular number (Tb.N) were (0.841±0.212)% in the mixed blank group and (4.497±0.413)% in the mixed treatment group (P<0.05). Bone mineral density (BMD) was (0.184±0.072)% in mixed blank group was and (0.615± 0.010)% in mixed experimental group (P<0.05). Conclusion: CGRP and SP could promote osteogenesis individually and promote osteogenesis synergistically.

Key words: calcitonin gene-related peptide, substance P, gelatin microspheres, alveolar bone, osteogenesis