| Mechanical environment, as a native survival one, is very complicated and constituted of many different kinds of forces, such as the forces in vitro or between tissues and cells, and the interactive intracellular stress during the process of formation and remodification of cytoskeletons. All these forces regulate bodies' developments and cellular differentiations, which is particularly obvious in bone tissues.In previous studies, Cyclooxygenase-2(COX-2) is believed to be linked with inflammations and tumors. But in recent reports, COX-2 is found to play important roles in osteoblastic mechanotransduction and in bone remodification and resorptions in some ways. It was found that mechanical stretches, such as hydrostatic forces and pulsating fluid flow(PFF), could increase the expressions of COX-2 mRNA and then prostaglandins(PGs), and activate many signal pathways in osteoblasts. The alveolar's growth is regulated by many kinds of force factors. But up to now, the roles and actions of COX-2 in osteoblastic mechanotransdutions are not very clear yet. It is believed that the differentexpressions of COX-2 have crucial effects on osteoblasts' biological characteristics. The development of specific agonists and antagonists for COX-2 will help us to define the physiologic and pathophysiologic roles of PGs, and this may lead to new therapeutic ideas and approaches to restorations of alveolar, and control the bone absorptions.In this study we observed the characters of cyclooxyenase-2 expressions and distributions in rat alveolar osteoblasts in vivo or in vitro in different force environments. And we tried to find the suitable mechanical environment to benefit the reproduction and remodification of alveolar bone in oral clinical treatment.In this article we reported the design and facture of an appropriate apparatus to make press on alveolar osteoblast cells, the establishment of primary culture system and subculture system on mechanical loading on alveolar osteoblasts, the examination of the inducible expressions of COX-2 in different time and styles of forces loading, and the immunohistochemical locations of COX-2 in the developing rat tooth germs and the alveolars in unilateral mastication.Here is a simple description of our results:An appropriate apparatus to force cultured alveolar osteoblasts was successfully designed and made. It can provide a relatively steady and appropriate environment for cell growing, and hydrostatic compressive forces on cells in different time and styles effectively satisfy the experiments demands.Alveolar osteoblasts were primarily cultured with two steps digestive methods and purified according to the different anchorage potentials of osteoblasts from other types of cells. Our experiments confirm that cultured alveolar cells have some characters and phenotypes of osteoblasts, and can be used as a cultured model to study alveolar osteoblasts in vitro.By Immunocytochemical stain and Western blotting, we found that the expressions of COX-2 were gradually increased with the time extending in the same magnitude of forces loading, but the induced expressions under two kind of hydrostatic compressions have no significant differences.This study firstly reported the special and dynamic spatial and temporaldistributions of the expressions of COX-2 during various stages of the rat tooth germs development. It is expressed mainly in the oral epithelium, dental lamina, outer enamel epithelium, stratum intermedium and stellate reticulum at cap and bell stages.In our experiment the model of rat unilateral mastication was established by extraction, and the biological mechanical environments of alveolar and periodontium was changed. COX-2 inducible expressions were observed in rat alveolar osteoblasts and periodontal cells by immunohistochemical stains.This study firstly observed the characters of COX-2 expressions and distributions in rat alveolar osteoblasts in different force environments in vivo or in vitro.This data in our study suggest that mechanical stimuli... |
PDF Full Text Request