Hong Wang1,2,3, Hong Wang1,2,3, Xiaoyu Li1,2,3, Zijie Zhang1,2,3, Xiaolu Zhao1,2,3, Chunling Wang1,2,3, Fulan Wei1,2,3. 1. Department of Orthodontics, School and Hospital of Stomatology, Shandong University, Jinan, China. 2. Shandong Provincial Key Laboratory of Oral Tissue Regeneration, Jinan, China. 3. Shandong Engineering Laboratory for Dental Materials and Oral Tissue Regeneration, Jinan, China.
Abstract
BACKGROUND: Bone reconstruction of the maxillary bone defects is an urgent issue due to its functional and aesthetic influence. MicroRNAs (miRNAs) are a class of non-coding RNAs that function in diverse biological and pathological processes. Recently, microRNA-21 (miR-21) was reported to play significant roles in bone formation, suggesting that miR-21 can be novel biomarker and therapeutic target for bone remodelling and skeletal diseases. However, the role of miR-21 in maxillary bone defects remains unclear. OBJECTIVE AND METHODS: This study aimed to investigate the effect of miR-21 on the bone reconstruction by inducing maxillary bone defects in wild-type (WT) and miR-21 knockout (miR-21-KO) mice and explore these mice as maxillary bone defect models. RESULTS: Micro-computed tomography (micro-CT) and histochemistry showed that the miR-21-KO mice had reduced bone reformation ability compared with the WT mice. The expression levels of alkaline phosphatase (ALP) and osteocalcin (OCN) were dramatically decreased in the miR-21-KO mice. In addition, injection of miR-21 agomir intra-peritoneally into miR-21-KO mice (miR-21-KO+ agomir) following the maxillary bone defects surgery displayed a significantly enhanced bone formation -promoting ability, which indicated that miR-21 agomir could ameliorate maxillary bone defects in miR-21-KO mice in vivo. Furthermore, immunohistochemistry suggested that ALP and OCN expressions were prominently increased in miR-21-KO+ agomir mice. CONCLUSION: These findings demonstrated that miR-21 deficiency impaired bone reformation and miR-21 contributed to the bone reconstruction of the maxillary bone defects. The evidence also supported the use of WT and miR-21-KO mice as maxillary bone defect models for further research.
BACKGROUND: Bone reconstruction of the maxillary bone defects is an urgent issue due to its functional and aesthetic influence. MicroRNAs (miRNAs) are a class of non-coding RNAs that function in diverse biological and pathological processes. Recently, microRNA-21 (miR-21) was reported to play significant roles in bone formation, suggesting that miR-21 can be novel biomarker and therapeutic target for bone remodelling and skeletal diseases. However, the role of miR-21 in maxillary bone defects remains unclear. OBJECTIVE AND METHODS: This study aimed to investigate the effect of miR-21 on the bone reconstruction by inducing maxillary bone defects in wild-type (WT) and miR-21 knockout (miR-21-KO) mice and explore these mice as maxillary bone defect models. RESULTS: Micro-computed tomography (micro-CT) and histochemistry showed that the miR-21-KO mice had reduced bone reformation ability compared with the WT mice. The expression levels of alkaline phosphatase (ALP) and osteocalcin (OCN) were dramatically decreased in the miR-21-KO mice. In addition, injection of miR-21 agomir intra-peritoneally into miR-21-KO mice (miR-21-KO+ agomir) following the maxillary bone defects surgery displayed a significantly enhanced bone formation -promoting ability, which indicated that miR-21 agomir could ameliorate maxillary bone defects in miR-21-KO mice in vivo. Furthermore, immunohistochemistry suggested that ALP and OCN expressions were prominently increased in miR-21-KO+ agomir mice. CONCLUSION: These findings demonstrated that miR-21 deficiency impaired bone reformation and miR-21 contributed to the bone reconstruction of the maxillary bone defects. The evidence also supported the use of WT and miR-21-KO mice as maxillary bone defect models for further research.