ABSTRACT: miRNA expression data from callus in standard fracture healing models and from fibrous tissues in nonunion models in rats on post-fracture day 14
Project description:Profiling of miRNA expressions comparing standard fracture healing models with nonunion models in rats 12w, male, Sprague–Dawley rats were used in this study. Animals were randomized to receive either a surgical treatment that has been shown to produce a nonunion or to a standard stabilized closed femoral shaft fracture that is known to successfully heal. The details of these procedures have been previously described. Briefly, to produce standard healing models, a 1.2-mm diameter K-wire was inserted retrograde into the right femoral intramedullary canal and a closed transverse femoral shaft fracture was produced using a three-point bending apparatus with a drop weight . To produce the nonunion, the fractured site was additionally exposed, and the periosteum was cauterized circumferentially for a distance of 2 mm on each side of the fracture . Five animals from each group were euthanized on post-fracture day 14 for microarray analysis.
Project description:This is a study of femoral fracture healing in female rats 16 weeks old at fracture to compare intramedullary nailing, screw and plate fixation, and sham surgery. The sham surgery group received a surgical exposure of the femur, but no fracture, no plate, and no nail. Samples were collected at 1 day, 3 days, 1 week, 2 weeks, 4 weeks, and 6 weeks after surgery. Each sample is a pool of RNA from three rats from the same surgery group at the same time point after fracture. The middle third of the femur was collected with the cortical bone, fracture callus, and marrow elements. Mid-diaphyseal, simple, transverse fractures were induced by a Gigli saw. The no fracture sample was a time 0 control collected on the day of surgery from intact rats.
Project description:Genome-wide comparative gene expression analysis of callus tissue of osteoporotic mice (Col1a1-Krm2 and Lrp5-/-) and wild-type were performed to identify candidate genes that might be responsible for the impaired fracture healing observed in Col1a1-Krm2 and Lrp5-/- mice. To investigate bone healing in osteoporosis, we performed fracture healing studies in wild-type mice (C57BL/6 genetic background) and the low bone mass strains Col1a1-Krm2 and Lrp5-/- (Schulze et al., 2010; Kato et al., 2002). Osteotomy was set in femora of female mice and stabilized by a semi-rigid fixator to allow fast bone healing (RM-CM-6ntgen et al., 2010). 21 days post surgery we analyzed the fracture calli by biochemical/histological methods, as well as micro-computed tomography, and observed impaired fracture healing in Col1a1-Krm2 and Lrp5-/- mice in comparison to wild-type. To identify genes that may be responsible for the impaired healing in osteoporotic mice, we performed microarray analysis of three independent callus samples of each genotype. The callus tissue was taken 10 days after surgery, because extensive bone formation took place at this point.
Project description:This is a study of femoral fracture healing in female rats 16 weeks old at fracture to compare intramedullary nailing, screw and plate fixation, and sham surgery. The sham surgery group received a surgical exposure of the femur, but no fracture, no plate, and no nail. Samples were collected at 1 day, 3 days, 1 week, 2 weeks, 4 weeks, and 6 weeks after surgery. Each sample is a pool of RNA from three rats from the same surgery group at the same time point after fracture. The middle third of the femur was collected with the cortical bone, fracture callus, and marrow elements. Mid-diaphyseal, simple, transverse fractures were induced by a Gigli saw. The no fracture sample was a time 0 control collected on the day of surgery from intact rats. Keywords = rat Keywords = fracture Keywords = plate Keywords = nail Keywords = time Keywords = femur Keywords: time-course
Project description:A study of rat femoral fracture healing in young (6 weeks old at fracture), adult (26 weeks old at fracture), and old (52 weeks old at fracture) rats. Samples were collected at time of surgery (intact controls) and at 3 days, 1 week, 2 weeks, 4 weeks, and 6 weeks after fracture. Samples were the mid third of the femoral length including the external callus, cortical bone and marrow elements. Fracture was stabilized with an intramedullary rod prior to fracture with a Bonnarens and Einhorn device.
Project description:We reported the application of single-cell mRNA sequencing to identify a unique population of fibroblasts that exits in the fracture callus of bisphosphonate-treated rats. Such unique population of fibroblasts prevented fracture healing by secreting ECM. Further, it was found that these ECM-secreting fibroblasts were enriched for myeloid genes, suggesting a bone marrow orgin. After fractures were treated with local CGRP injection or Magnesium based biometal, such population of fibroblasts was cleared off, resulting in facilitated fracture healing of bisphosphonate-treated rats.
Project description:Bone fracture healing shows approximately 10-15% non-unions, although theoretically it has the potential of scarless regeneration. With regards to our aging society, a better understanding of the healing process is needed to allow for more sophisticated treatment options. Particular the early phase, which is a high complex and dynamic process in regards to nutrient and engery requirements. Here we investigate the proteomic (and metabolic) characteristics of the local microenvironment from successful (in young female Sprague-Dawley rats) and biologically compromised (in aged female rats with a minimum litter of three)bone reneration at day 3, 7 and 14 after osteotomy.
Project description:A study of rat femoral fracture healing in young (6 weeks old at fracture), adult (26 weeks old at fracture), and old (52 weeks old at fracture) rats. Samples were collected at time of surgery (intact controls) and at 3 days, 1 week, 2 weeks, 4 weeks, and 6 weeks after fracture. Samples were the mid third of the femoral length including the external callus, cortical bone and marrow elements. Fracture was stabilized with an intramedullary rod prior to fracture with a Bonnarens and Einhorn device. Keywords: time-course
Project description:Interleukin-6 (IL-6) is highly upregulated in response to skeletal injury, suggesting it plays a role in the inflammatory phase of fracture repair. However, the impact of IL-6 on successful repair remains incompletely defined. Therefore, we investigated IL-6 in fracture repair using 12-week old IL-6 global knockout mice (IL-6 KO) and two models of fracture repair: full fracture and stress fracture. Callus formation 14 days after full fracture did not differ between IL-6 knockout mice and controls. However, IL-6 KO mice had an enhanced response 7 days after stress fracture compared to control, with increased callus (p=0.020) and bone formation (p=0.045). IL-6 KO did not alter the recruitment of neutrophils or macrophages to the stress fracture callus. IL-6 KO also did not alter the number of osteoclasts in the stress fracture callus. Based on RNA-seq, IL-6 KO resulted in only modest alterations to the gene expression at early time points after stress fracture. Wnt1 was more highly upregulated in IL-6 KO callus at both day 1 (fold change 12.5 vs. 5.7) and day 3 (fold change 4.7 vs. 1.9) compared to controls. Finally, using tibial compression to induce bone formation, we found that IL-6 KO directly impacted osteoblast function, increasing the propensity for woven bone formation. Herein, we report that IL-6 knockout enhanced formation of callus and bone following stress fracture injury, likely through direct action on the osteoblast’s ability to produce woven bone. This suggests a novel role of IL-6 as a suppressor of intramembranous bone formation.