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Int. j. morphol ; 38(5): 1398-1404, oct. 2020. tab, graf
Article in English | LILACS | ID: biblio-1134455


SUMMARY: The objective of this study were bone defect complications that occur due to traumas or infections. Bone grafts are required to provide support, fill gaps and improve biological repair in skeletal damage. Dexamethasone plays role in calcium signaling modulation and used in diseases. Aim of this study was to evaluate osteonectin and osteopontin expressions in new bone development after dexamethasone application on tibial bone defects. Rats were divided into defect, defect+graft and defect+graft+dexamethasone treated groups. Tibial bone defect created, and rats were kept immobile for 28 days. Alloplastic material was placed in defect area in second and group third groups. 2.5 mg/kg Dex and normal saline were injected to dexamethasone and defect groups twice a week for 56 days. Inflammation and congestion were increased in defect and defect+graft groups. Defect+graft+dexamethasone group; increased number of osteoblast and osteocyte cells, dense bone matrix, formation of new bone trabeculae was observed. Defect+graft group; osteonectin expression in graft regions, osteoblast cells, some connective tissue cells and fibers were seen whereas in defect+graft+dexamethasone group; osteopontin expression in osteoblast and osteocyte cells of new bone trabeculae were observed. Dexamethasone may lead to formation of new bone trabeculae into the graft material resulting in increased osteoconduction and osteoinductive effect for differentiation of osteon.

RESUMEN: Los defectos óseos son complicaciones que ocurren debido a traumas o infecciones. Se requieren injertos óseos para proporcionar apoyo, llenar los espacios y mejorar la reparación biológica en el hueso dañado. La dexametasona desempeña un papel importante en la modulación de la señalización del calcio y se usa en enfermedades. El objetivo de este estudio fue evaluar las expresiones de osteonectina y osteopontina en el desarrollo óseo después de la aplicación de dexametasona en defectos óseos tibiales. Las ratas se dividieron en grupos: defecto, defecto + injerto y defecto + injerto + grupos tratados con dexametasona. Se creó un defecto óseo tibial, y las ratas se mantuvieron inmóviles durante 28 días. El material aloplástico se colocó en el área del defecto en el segundo y tercer grupo. Se inyectaron 2,5 mg / kg de dexametasona y solución salina normal a grupos de defectos dos veces por semana durante 56 días. La inflamación y la congestión aumentaron en los grupos de defectos y defectos + injerto; En el grupo defecto + injerto + grupo tratado con dexametasona se observó un aumento en el número de osteoblastos y osteocitos, de matriz ósea densa y en la formación de nuevas trabéculas óseas. En el grupo defecto + grupo de injerto se observó la expresión de osteonectina en las áreas de injerto, osteoblastos, algunas células y fibras de tejido conectivo, mientras que en el grupo defecto + injerto + dexametasona se observó la expresión de osteopontina en osteoblastos y osteocitos y formación de nuevas trabéculas óseas . En conclusión la dexametasona puede conducir a la formación de nuevas trabéculas óseas en el material de injerto, lo que resulta en un aumento de la osteoconducción y un efecto osteoinductivo para la diferenciación del osteón.

Animals , Male , Rats , Tibia/surgery , Tibia/drug effects , Dexamethasone/administration & dosage , Bone Transplantation , Tibia/pathology , Bone Regeneration , Immunohistochemistry , Osteonectin/physiology , Bone Remodeling , Rats, Wistar , Disease Models, Animal , Osteopontin/physiology
Article in English | IMSEAR | ID: sea-157382


Osteopontin (OPN) is phosphorylated sialic acid –rich non-collagenous bone matrix protein. OPN is found in several biological fluids including human plasma, serum, breast milk and urine.OPN was named for its function as a bridge between cells and minerals. OPN has been implicated as an important factor in bone remodeling. Osteopontin is expressed in immune cells, including macrophages, neutrophils, dendritic cells with varying kinetics. OPN influences cell mediated immunity and has Th 1 cytokine functions .OPN is overexpressed in cancers of lung, breast, colorectal, stomach and ovary.OPN is found in atheromatous plaques within arteries. OPN plays an important role during both acute and chronic inflammation. OPN is upregulated in tissues during several pathological process including atherosclerosis, valve stenosis, myocardial infarction and rheumatic arthritis. OPN is a key cytokine regulating tissue repair. OPN’s plasma levels are elevated in overweight and obesity.

Atherosclerosis , Humans , Inflammation , Obesity , Osteopontin/blood , Osteopontin/chemistry , Osteopontin/immunology , Osteopontin/metabolism , Osteopontin/physiology , Osteopontin/urine , Vascular Calcification