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Possible alternative treatment for mandibular asymmetry by local unilateral IGF-1 injection into the mandibular condylar cavity: Experimental study in mice

2017; Elsevier BV; Volume: 152; Issue: 6 Linguagem: Inglês

10.1016/j.ajodo.2017.05.023

1097-6752

Sari Fukaya, Hiroyuki Kanzaki, Yutaka Miyamoto, Yuki Yamaguchi, Yoshiki Nakamura,

Craniofacial Disorders and Treatments

•IGF-1 was injected unilaterally into the mandibular condylar cavity in mice. •Local IGF-1 injection induced a lateral shift of the mandible. •Local injection into the condylar cavity induced endochondral growth and ossification. •Chondrogenic and osteoblastic gene expression was upregulated. •No systemic effects were found. Introduction The purpose of this study was to investigate whether a local unilateral IGF-1 injection into the mandibular condylar cavity can induce unilateral endochondral mandibular growth without any systemic adverse effects. Methods Seventy-five 3-week-old male Jcl:ICR mice were used in this study. The mice were divided into 2 groups: control group (n = 22) and IGF-1 group (n = 53). In the IGF-1 group, human IGF-1 was injected into the right mandibular condylar cavity, and phosphate-buffered saline solution was injected into the left cavity, 3 times per week for 10 weeks. Results There was no significant difference in body weight, serum human IGF-1 concentration, and soft tissue thickness of the cheeks including the masseter muscles between the 2 groups. Unilateral IGF-1 injection induced a lateral shift of the mandible to the contralateral side, and microcomputed tomogtraphy analysis showed that unilateral IGF-1 injection induced endochondral growth in the condyle. Col2, Ihh, and Runx2 were extensively upregulated by the local unilateral IGF-1 injection in real-time reverse transcription polymerase chain reaction analysis. Proliferation marker KI67, IGF-1 signaling molecule AKT1, and chondrogenic differentiation marker Col2 were strongly expressed in the IGF-1 injected condyle by immunohistochemistry. Vital labeling showed that the distance between the labels was increased in the IGF-1 injection group compared with that of the control group. Conclusions The results verified in this study indicated that local unilateral IGF-1 injection into the mandibular condylar cavity successfully induced unilateral endochondral mandibular growth in mice without any systemic adverse effects. Thus, local unilateral IGF-1 injection into the mandibular condylar cavity could be a useful alternative for mandibular asymmetry therapy during the growth period. However, additional experimental and clinical studies will be necessary to prove the real effect of this new therapy.