The histological effects of copper and zinc on chick embryo skeletal tissues in organ culture

Abstract

1. The effects of copper and zinc on organ cultures of chick embryo cartilage and bone maintained in low-trace-metal, chemically defined media for up to 8 d were studied macro-scopically, histologically and histochemically. Length and wet-weight measurement of explants were assessed statistically.2. No effects were found with Cu concentrations of 0·5–1·5μg/ml medium. Between concentrations of 5 and 40μg Cu/ml medium, lengths and wet-weights of cartilage cultures decreased significantly (P< 0·001) compared with controls. The decrease was directly proportional to increasing Cu concentration, and that of the length was greater with increasing period of culture (P< 0·001).3. With 5–20μg Cu/ml medium cartilage and bone became yellow in colour, and chondrocytes were swollen, rounded and basophilic. They were detached from their lacunae and the quantity of matrix was reduced. Loss of alkaline phosphatase (EC3.1.3.1) activity and disappearance of glycogen accompanied the degeneration. Osteogenesis ceased, cells failed to divide and mature, lost their enzymes and died. Cu did not accumulate in the bone matrix.4. The direct toxic effects of Cu for cartilage and bone may underlie some of the skeletal changes in hepatolenticular degeneration (Wilson’s disease).5. As Zn concentrations were increased from 2·5 to 7·5μg/ml medium, lengths and wet-weights of cartilaginous cultures were significantly increased (P< 0·001). As Zn concentrations were further increased (from 10 to 40μg/ml medium), lengths and wet-weights were significantly decreased (P< 0·001).6. Zn stimulated chondrocyte division and vacuolation of cytoplasm. With higher Zn concentrations toxic changes of granular basophilia, lacunar detachment and necrosis were seen. Differentiation and functioning of osteoblasts, osteoclasts and chondroclasts were stimulated by Zn.7. Zn was found in bone matrix, osteoblasts, osteocytes and hypertrophied chondrocytes.

Zinc as a Therapeutic Agent in Bone Regeneration

“…Dietary zinc deficiency has been linked to impaired skeletal development and bone growth in humans and animals (Figure 1) [51][52][53][54][55][56][57][58][59][60][61][62]. Early experiments with rats to determine if dietary zinc was essential for growth were complicated by co-reduction of essential vitamins and amino acids in zinc-depleted media.…”

“…Consistent with impaired bone formation and reduced growth in zinc-deficient animals and humans [51,57,61,65], zinc also affects chondrogenesis (Figure 2). Growth of chick embryo long bone cartilage anlage positively correlates with the amount of zinc in organ culture media [62]. In contrast, growth plate chondrocyte proliferation is reduced and apoptosis is increased in newly hatched chicks fed a zinc-deficient diet (10 mg Zn/kg chow) as compared to pair-fed, newly hatched chicks fed a normal diet (68 mg Zn/kg) [164].…”

Manifestations rhumatologiques associées à la maladie de Wilson

“…Dans cette population franç aise de MW, la moyenne des Z-scores était normale aux deux sites ; la prévalence d'ostéoporose définie selon l'OMS (T-score < −2,5) était de 9 % (5 % chez les femmes et 15 % chez les hommes), ce qui était plus faible que les chiffres obtenus sur la série densitométrique adulte qui portait sur 21 patients. Dans cet échantillon, la prévalence des fractures périphériques était de 65 % chez les hommes et 34 La perte osseuse et sa relation avec la MW restent donc discutées.…”

“…Dans la littérature, une seule étude ancienne a évalué l'effet du Cu in vitro sur le tissu squelettique d'embryons de poulet [34]. Pour des concentrations moyennes de Cu (5 et 20 g/ml), les auteurs ont montré une réduction de l'épaisseur de la matrice osseuse, un arrêt de l'ostéogenèse, et un arrêt de la division et de la maturation cellulaire des ostéoblastes.…”

Microscopic X-ray fluorescence analysis of human dental calculus using synchrotron radiation

“…16 In addition, an injurious effect of Cu on mineralization has been reported, affecting the crystal size in synthetic apatite 18 and skeletal bone. 19 Cu is also found in a number of enzymes and is involved in connective tissue and structural protein formation; it also participates inhibiting growth of supragingival plaque bacteria and thus reducing bacterial acid production.…”