acid-phosphatase and Tibial-Fractures

This study examined the impact of an interleukin-6 (IL-6) knockout on fracture healing in terms of histological and biomechanical responses. Following IACUC approval, tibial fractures were produced in 4- to 6-week-old IL-6 knockouts (n = 35) and wild-type mice (n = 36) and harvested along with contralateral limbs at 2 and 6 weeks postsurgery. Histology quantified stage of healing, lymphocyte infiltration, TRAP+ cells, and osteocalcin deposition. Bend testing established maximum load and stiffness. Based on normality assessments, Mann-Whitney U or independent t-tests were used for data analysis using a p-value threshold of 0.05. Stage of healing, lymphocyte infiltration, and osteocalcin deposition were similar for all time points (p ≥ 0.243). TRAP+ cell counts were reduced approximately 10-fold in the knockout at 2 weeks (p = 0.015) but were similar at 6 weeks (p = 0.689). Force-to-failure in knockouts was approximately 40% that of wild-type mice at 2 weeks (p = 0.040) but similar at 6 weeks (p = 0.735). Knockout bone was about 25% less stiff at 2 weeks but approximately 60% stiffer at 6 weeks (p ≥ 0.110). The absence of IL-6 during early fracture healing significantly reduced osteoclastogenesis and impaired callus strength. By 6 weeks, most histological and biomechanical parameters were similar to fractures in wild-type bone.

Topics: Acid Phosphatase; Animals; Bony Callus; Disease Models, Animal; Elasticity; Fracture Healing; Interleukin-6; Isoenzymes; Lymphocytes; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Osteocalcin; Stress, Mechanical; Tartrate-Resistant Acid Phosphatase; Tibial Fractures

An experimental rat model was used to test the hypothesis that in osteoporosis (OP) the molecular composition of the extracellular matrix in the fracture callus is disturbed. OP was induced at 10 weeks of age by ovariectomy and a vitamin D(3)-deficient diet, and sham-operated animals fed normal diet served as controls. Three months later a closed tibial fracture was made and stabilized with an intramedullary nail. After 3 and 6 weeks of healing, the animals were killed and the fracture calluses examined with global gene expression, in situ mRNA expression, and ultrastructural protein distribution of four bone turnover markers: osteopontin, bone sialoprotein, tartrate-resistant acid phosphatase, and cathepsin K. Global gene expression showed a relatively small number of differently regulated genes, mostly upregulated and at 3 weeks. The four chosen markers were not differently regulated, and only minor differences in the in situ mRNA expression and ultrastructural protein distribution were detected. Gene expression and composition of fracture calluses are not generally disturbed in experimental OP.

Topics: Acid Phosphatase; Animals; Biomarkers; Bony Callus; Cathepsin K; Estrogens; Female; Fractures, Bone; Gene Expression; Isoenzymes; Osteoporosis; Ovariectomy; Rats; Rats, Wistar; Tartrate-Resistant Acid Phosphatase; Tibia; Tibial Fractures; Vitamin D; Vitamin D Deficiency

It has been suggested that acid phosphatase activity is present in newly formed bone matrix at sites of endochondral ossification in rabbit fracture calluses. Because acid phosphatases are usually found intracellularly, it was decided to test this possibility more rigorously. Tissue from 10- and 14-day healing rabbit fractures was subjected to a series of critical tests for acid phosphatases with a pH optimum of 5.0. Fluoride, tartrate and molybdate were used as potential inhibitors of acid phosphatase activity. The effects of several counterstaining protocols were also investigated. A fluoride- and tartrate-resistant acid phosphatase is located in osteoclasts and mononuclear phagocytes. Diffuse staining of the bone matrix is seen, but it is dependent upon the length of incubation in the substrate medium and the distance from the acid phosphatase-reacting cells. It is concluded that the coloration of the bone matrix is probably caused by diffusion of the dye and reaction product and is, therefore, artifactual.

Topics: Acid Phosphatase; Animals; Artifacts; Bone Matrix; Bony Callus; Chondrocytes; Fluorides; Fracture Healing; Molybdenum; Osteoblasts; Osteoclasts; Osteogenesis; Phagocytes; Rabbits; Staining and Labeling; Tartrates; Tibial Fractures

Periosteum was obtained within 10 days of injury from the site of 17 adult tibial diaphyseal fractures during internal fixation. Osteogenic cells, non-osteogenic cells and vascular elements were identified in situ using a variety of techniques. In all cases, the periosteum was thickened with randomly distributed plaques of cartilage and bone. Cells covering newly formed bone trabeculae expressed osteocalcin. Lectin-binding revealed high vascularity. Few mast cells were observed. Macrophages and acid phosphatase positive cells, some multinucleate, were observed in abundance. These findings suggest that the repair of the adult human diaphyseal fracture is similar to that of experimental fractures in rapidity of onset, high vascularity and in bone and cartilage formation. They differ in the fact that chondrogenesis and osteogenesis appear to be simultaneous in human fractures but sequential in experimental fractures. The paucity of mast cells suggests that they probably play no significant role in the repair of the human fractures.

Topics: Acid Phosphatase; Adolescent; Adult; Aged; Cartilage; Diaphyses; Fracture Healing; Humans; Middle Aged; Osteocalcin; Osteogenesis; Periosteum; Tibial Fractures; Transforming Growth Factor beta

Topics: Acid Phosphatase; Animals; Bone Resorption; Bony Callus; Enzyme Activation; Galactosidases; Hexosaminidases; Hydrolases; Microscopy, Electron; Organ Culture Techniques; Osteoclasts; Parathyroid Glands; Rats; Tibia; Tibial Fractures; Time Factors; Tissue Extracts

Topics: Acid Phosphatase; Alkaline Phosphatase; Animals; Bone Regeneration; Bone Resorption; Fractures, Bone; Guinea Pigs; Humans; Osteogenesis; Research; Tibial Fractures