Effect of chitosan scaffold on bone healing in rabbit calvarial defect

The aim of this study was to evaluate the effect of 3D 2% w/v chitosan scaffolds on new bone formation in a rabbit calvarial defect. Two bi-cortical skull defects were prepared in 16 male rabbits and divided into two groups: autogenous (positive controls) and chitosan scaffolds (experimental groups). The animals were sacrificed at 2, 4, 8, and 12 weeks. New bone formation was evaluated by micro-CT and histomorphometric analysis. The positive control group demonstrated significantly greater bone formation. The experimental groups showed viable lamellar bone with osteoblasts forming bone from the defect margin. Histomorphometric analysis showed an increased percentage of new bone formation over time, and a micro-CT analysis also showed an increased percentage of bone volume over time. Although the new bone formation was not as good as the positive control groups, our in-house fabricated chitosan scaffolds presented good biocompatibility and osteoconductive properties in a rabbit calvarial defect

Transcription regulation of cathepsin K controlled by bone resorption related cytokines

PLEASE NOTE: This work is protected by copyright. Downloading is restricted to the BU community: please click Download and log in with a valid BU account to access. If you are the author of this work and would like to make it publicly available, please contact [email protected] (D.Sc.D.)--Boston University, Henry M. Goldman School of Dental Medicine, 1999 (Pediatric Dentistry).Includes bibliographical references (leaves 68-79).Osteoclasts function as bone and cartilage-resorbing cells to modulate bone formation and metabolism. They posses a highly specialized proton generating mechanism for the rapid dissolution of bone mineral and secrete collagenases, cathepsin K and other hydrolyses active in the degradation of bone matrix proteins. To date, several cytokines have been implicated in osteoclast formation and activity. Some cytokines, including IL-1a, induce bone resorption whereas the others, such as IFN-y, inhibit bone resorption. It is possible that cytokines may control physiological and pathological bone resorption through the regulation of osteoclast gene expression including cathepsin K. Cathepsin K is abundantly and selectively expressed in osteoclast, and is a key protease responsible for matrix protein degradation in normal bone remodeling as well as in pathological processes, such as periodontal disease and osteoporosis. lnterferon-y (IFN-y) is a glycoprotein produced by activated lymphocyte and natural killer cells and has multiple biologic effects, including antiviral, antitumor, and cell growth inhibitory activities. Like many other cytokines, IFN-y also functions in bone metabolism. IFN-y inhibits osteoclastic bone resorption, but the mechanism responsible for this inhibition is unknown. IL-1a is pluripotent cytokine produced by monocytes/macrophages that has various effects on a wide variety of cells including osteoclast. I L-1 a is the most potent osteoclast-activating factor that ... [TRUNCATED

Responses of human normal osteoblast cells and osteoblast-like cell line, MG-63 cells, to pulse electromagnetic field (PEMF)

The objective of this in vitro study is to investigate the effect of pulsed electromagnetic field (PEMF) on cellular proliferation and osteocalcin production of osteoblast-like cell line, MG-63 cells, and human normal osteoblast cells (NHOC) obtained from surgical bone specimens. The cells were placed in 24-well culture plates in the amount of 3x104 cell/wells with 2 ml αMEM media supplemented with 10% FBS. The experimental plates were placed between a pair of Helmoltz coils powered by a pulse generator (PEMF, 50 Hz, 1.5 mV/cm) in the upper compartment of a dual incubator (Forma). The control plates were placed in the lower compartment of the incubator without Helmotz coils. After three days, the cell proliferation was measured by the method modified from Mossman (J. Immunol Methods 1983; 65: 55-63). Other sets of plates were used for osteocalcin production assessment. Media from these sets were collected after 6 days and assessed for osteocalcin production using ELISA kits. The data were analyzed using a one-way analysis of variance (ANOVA). The results showed that MG-63 cells from the experimental group proliferated significantly more than those from the control group (20% increase, p<0.05). No significant difference in osteocalcin production was detected between the two groups. On the other hand, NHOC from the experimental group produced larger amount of osteocalcin (25% increase, p<0.05) and proliferated significantly more than those from the control group (100% increase, p<0.05). In conclusion, PEMF effect on osteoblasts might depend on their cell type of origin. For osteoblast-like cell line, MG-63 cells, PEMF increased proliferation rate but not osteocalcin production of the cells. However, PEMF stimulation effect on human normal osteoblast cells was most likely associated with enhancement of both osteocalcin production and cell proliferation

Responses of human normal osteoblast cells and osteoblast-like cell line, MG-63 cells, to pulse electromagnetic field (PEMF)

Abstract The objective of this in vitro study is to investigate the effect of pulsed electromagnetic field (PEMF) on cellular proliferation and osteocalcin production of osteoblast-like cell line, MG-63 cells, and human normal osteoblast cells (NHOC) obtained from surgical bone specimens. The cells were placed in 24-well culture plates in the amount of 3x10 4 cell/wells with 2 ml αMEM media supplemented with 10% FBS. The experimental plates were placed between a pair of Helmoltz coils powered by a pulse generator (PEMF, 50 Hz, 1.5 mV/cm) in the upper compartment of a dual incubator (Forma). The control plates were placed in the lower compartment of the incubator without Helmotz coils. After three days, the cell proliferation was measured by the method modified from Mossman (J. Immunol Methods 1983; 65: 55-63). Other sets of plates were used for osteocalcin production assessment. Media from these sets were collected after 6 days and assessed for osteocalcin production using ELISA kits. The data were analyzed using a one-way analysis of variance (ANOVA). The results showed that MG-63 cells from the experimental group proliferated significantly more than those from the control group (20% increase, p&lt;0.05). No significant difference in osteocalcin production was detected between the two groups. On the other hand, NHOC from the experimental group produced larger amount of osteocalcin (25% increase, p&lt;0.05) and proliferated significantly more than those from the control group (100% increase, p&lt;0.05). In conclusion, PEMF effect on osteoblasts might depend on their cell type of origin. For osteoblast-like cell line, MG-63 cells, PEMF increased proliferation rate but not osteocalcin production of the cells. However, PEMF stimulation effect on human normal osteoblast cells was most likely associated with enhancement of both osteocalcin production and cell proliferation