Effect of dolomite on the repair of bone defects in rats: histological study
Eduardo Moreschi1, Luzmarina Hernandes2, Jailson Araujo Dantas1, Maria Angélica Raffaini Covas Pereira da Silva1, Ana Regina Casaroto1 and Ciomar Aparecida Bersani-Amado1
1Department of Pharmacy and Pharmacology, Inflammation Laboratory, University of Maringá, Maringá-PR, Brazil and 2Department of Morphological Sciences, Histology Laboratory, University of Maringá, Maringá-PR, Brazil.
Offprint requests to: Prof. Dra. Ciomar Aparecida Bersani-Amado, Department of Pharmacy and Pharmacology/University of Maringá, Avenida Colombo, 5790, Maringá PR CEP: 87020-900, Brazil. e-mail: firstname.lastname@example.org
Summary. The aim of the present study was to evaluate histologically and radiographically the tissue response to dolomite [CaMg(CO3)2] and its osteogenic potential in the repair of bone cavities in the calvaria of rats. A bone defect 10 mm in diameter and 1 mm deep was made in the calvaria of male Wistar rats. The defects were filled with dolomite, inorganic bovine bone (positive control), or coagulum (negative control). The animals were euthanized 7, 15, 30, and 60 days after surgery, and specimens were collected for radiographic and microscopic analyses. The bone defects were processed for paraffin embedding and H&E staining. The histological study revealed that dolomite stimulated a moderate inflammatory response, with programmed cell death in the first 15 days, compared to bovine bone which showed a moderate to intense acute response. In the chronic phase, the inflammatory response was characterized by the occurrence of macrophages organized as epithelioid cells in the dolomite group, and giant cells in the bovine-bone group. Fibrosis developed in all three groups; however, encapsulation of the fragments, reabsorption, and osteoconductive activity occurred only in the defects filled with bovine bone. The radiographic analysis showed that the bovine bone was most efficient in the repair of the defects, followed by the dolomite and the coagulum. This study demonstrated that the dolomite stimulated a moderate acute inflammatory response with programmed cell death, and a chronic inflammatory response by means of the phagocytic mononuclear system. Although osteo-conductive activity was not shown, the dolomite favored the repair process, compared to the coagulum group. Histol Histopathol 25, 1547-1556 (2010)
Key words: Dolomite, Inorganic bovine bone, Bone repair, Histological and radiographic study