Yong-Gun Kim1, Jin-Woo Park1, Jae-Mok Lee1, Jo-Young Suh1, Jae-Kwan Lee2, Beom-Seok Chang2, Heung-Sik Um3, Jae-Young Kim4, Youngkyun Lee5. 1. Department of Periodontology, School of Dentistry, Kyungpook National University, Daegu 700-412, Republic of Korea. 2. Department of Periodontology, Gangneung-Wonju National University College of Dentistry, Gangneung 210-702, Republic of Korea. 3. Department of Periodontology, Gangneung-Wonju National University College of Dentistry, Gangneung 210-702, Republic of Korea. Electronic address: hsum@gwnu.ac.kr. 4. Department of Biochemistry and Institute for Hard Tissue & Bio-tooth Regeneration (IHBR), School of Dentistry, Kyungpook National University, Daegu 700-421, Republic of Korea. 5. Department of Biochemistry and Institute for Hard Tissue & Bio-tooth Regeneration (IHBR), School of Dentistry, Kyungpook National University, Daegu 700-421, Republic of Korea. Electronic address: ylee@knu.ac.kr.
Abstract
OBJECTIVE: The interleukin-17 (IL-17) family is a group of pro-inflammatory cytokines that are produced by a subset of helper T cells. IL-17 family members are not only involved in the immune response of tissues but also play a role in bone metabolism. Although the role of IL-17 in osteoclast-mediated bone resorption has been extensively studied, its role during osteoblast-mediated bone formation has rarely been investigated. In this study, we examined the effect of IL-17 on osteogenesis in rats both in vitro and in vivo. DESIGN: To evaluate osteogenesis in vitro, rat calvarial osteoblast precursor cells were cultured for 14 days in osteogenic medium with or without 50ng/mL IL-17. Osteogenic activity was evaluated by alkaline phosphatase and alizarin red staining. The mRNA expression of alkaline phosphatase, osteocalcin, and osterix was also measured by using real-time PCR. To test whether IL-17 affects bone formation in vivo, bone filling was examined by micro-computed tomography and histological observations at 8 weeks after critical-sized defects were made in rat calvaria. RESULTS: The presence of IL-17 significantly reduced alkaline phosphatase and alizarin red staining and the expression of alkaline phosphatase, osteocalcin, and osterix in vitro. IL-17 also significantly inhibited the filling of calvarial defects in vivo. CONCLUSION: IL-17 exerted a negative effect on osteogenesis in a rat model. In contrast to the previously reported beneficial effect on osteogenic differentiation of human mesenchymal stem cells, our results suggest a species or cell type-specific role for IL-17 in bone formation.
OBJECTIVE: The interleukin-17 (IL-17) family is a group of pro-inflammatory cytokines that are produced by a subset of helper T cells. IL-17 family members are not only involved in the immune response of tissues but also play a role in bone metabolism. Although the role of IL-17 in osteoclast-mediated bone resorption has been extensively studied, its role during osteoblast-mediated bone formation has rarely been investigated. In this study, we examined the effect of IL-17 on osteogenesis in rats both in vitro and in vivo. DESIGN: To evaluate osteogenesis in vitro, rat calvarial osteoblast precursor cells were cultured for 14 days in osteogenic medium with or without 50ng/mL IL-17. Osteogenic activity was evaluated by alkaline phosphatase and alizarin red staining. The mRNA expression of alkaline phosphatase, osteocalcin, and osterix was also measured by using real-time PCR. To test whether IL-17 affects bone formation in vivo, bone filling was examined by micro-computed tomography and histological observations at 8 weeks after critical-sized defects were made in rat calvaria. RESULTS: The presence of IL-17 significantly reduced alkaline phosphatase and alizarin red staining and the expression of alkaline phosphatase, osteocalcin, and osterix in vitro. IL-17 also significantly inhibited the filling of calvarial defects in vivo. CONCLUSION:IL-17 exerted a negative effect on osteogenesis in a rat model. In contrast to the previously reported beneficial effect on osteogenic differentiation of human mesenchymal stem cells, our results suggest a species or cell type-specific role for IL-17 in bone formation.