Changes Of Osteocyte Dendrites And Lacunar Canalicular In Mandibular Osteoporosis

This study aimed to investigate the structural and functional changes in osteocyte bodies, dendritic networks, and lacunar canalicular networks in mandibular osteoporosis in mice following menopause. Female C57BL/6J mice (8 weeks old, n=6) were randomly assigned to either a sham or an ovariectomized (OVX) group, followed by humane euthanasia 12 weeks postoperatively (No.XJTUAE2024-1099). The mandibles were subjected to immunofluorescence staining for F-actin and immunohistochemical stainning for matrix metalloproteinase 13 (Mmp13) and cathepsin K (Ctsk). Specimens were also embedded in methyl methacrylate and stained to visualize the lacunar-canalicular system (LCS), which was further characterized using SEM. And detection of Ctsk and Mmp13 was performed using RT-PCR. Two distinct lucaner shapes were observed in the mandible: osteocyte cell bodies in the alveolar bone were round, whereas those in the cortical bone were elongated and fusiform. In the OVX group, both the number and connectivity of dendrites in the embedded osteocytes of the alveolar and cortical regions were significantly reduced. Additionally, the OVX condition led to a decrease in canalicualr density within the mandible, likely resulting from the degeneration or apoptosis of osteocytes due to estrogen withdrawal. Notably, the expression level of Ctsk and Mmp13 increased in both mRNA and protein forms, indicating the activation of matrix remodeling in the perilacunar-canalicular regions. This study elucidates the alterations and underlying mechanisms affecting the dendritic network and lacunar-canalicular systems of mandibular osteocytes in postmenopausal osteoporosis, providing valuable insights into oral bone lesions associated with this condition .