Calcitonin and fracture healing. An experimental study on rats

Abstract

The effects of systemically administered calcitonin (CT) on fracture healing were analyzed in an experimental study on rats. The healing of a fracture was followed from 3 days up to 9 weeks postoperatively. Half of the rats in each age group were given daily CT 10 MRC-U/kg body wt s.c. Mechanical properties of the healing tibial fractures (tension strength) as well as various connective tissue components of the callus tissue were analyzed. No difference in the radiological or microscopical appearance of the fractures was detectable between the animals receiving CT and the controls. In the biochemical analysis matrix production as assessed from the concentrations of nitrogen, hexosamines, and hydroxyproline within the callus followed the usual lines of undistributed fracture union without any difference between the groups with and without CT. No differences could be detected in the mineralization of the callus between the specimens from animals receiving CT and those without. The tensile strength values of the fractures increased almost linearly up to 9 weeks. At 1 week the tensile strength values for fractures union in the animals without CT were approximately 50% higher, but later on no differences could be detected between the groups. These results indicate that although in the early phases of long-term CT therapy collagen synthesis may be impaired, there will be no effect on the net content of collagen or calcifying tissue in the callus or on the mechanical strength of healing fractures.

Calcium Metabolism and Oxidative Stress in Bone Fractures: Role of Antioxidants

“…Of the above studies, they examined the effect of calcitonin upon secondary (osteocartilaginous) callus formation. In some of these studies, it was not possible to detect any beneficial effect of calcitonin on fracture healing between the animals [72,73]. In other studies calcitonin was found to have an adverse effect by way of decreased collagen formation and mineralization as well as decreased callus strength [73,74].…”

Estudo do reparo ósseo com matriz óssea bovina desvitalizada e calcitonina em ratos

“…A matriz óssea bovina desvitalizada, como todas as modalidades de enxerto, está sujeita a influência de fatores próprios do organismo receptor, como tensão de oxigênio, desnutrição protéica, doenças metabólicas, hormônios e vitaminas, sendo a velocidade da reconstrução óssea relacionada aos níveis de fósforo, cálcio e de calcitonina, um hormônio com ação direta no metabolismo destes minerais e fator de grande importância na recuperação e manutenção da homeostase óssea. Por possuir ação analgésica, antiinflamatória e antiosteoclástica, a calcitonina é utilizada no tratamento de distúrbios clínicos e biológicos caracterizados por excessiva remodelação óssea em humanos 7,8,9,10,11,12 .…”

“…Ziegler e Delling 10 relataram que a calcitonina promove aceleração do processo regenerativo de defeito ósseo sem enxertia, em ratos. Paavolainen e col. 11 não encontraram diferenças nos aspectos radiográficos, microscópicos e biomecânicos em fraturas de tíbias de ratos tratados com calcitonina. Guarniero e col. 9 estudaram a influência da calcitonina e da desnutrição protéica, isoladas e associadas, na resistência mecânica e na rigidez do tecido ósseo em ratos, observando que a calcitonina favoreceu a neoformação óssea, reduzindo a ocorrência de pseudartrose.…”

Major fibrillar collagens and fibronectin in an experimental nonunion: An immunohistochemical study

“…Our experiences with Northern analysis in the same animal model has shown that the regulation of collagen genes is altered, impairing the normal reparative fracture healing cascade (Ekholm et al 1995). The collagens produced in the matrix of a healing fracture can be quantitated by biochemical methods (Penttinen 1972, Paavolainen et al 1989). However, these methods cannot localize the proteins, and therefore the distribution of specific collagens during fracture healing was studied by immunohistochemistry (Lane et al 1986).…”