The histological effects of copper and zinc on chick embryo skeletal tissues in organ culture.
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 macroscopically, histologically and histochemically. Length and wet-weight measurement of explants were assessed statistically. 2. No effects were found with Cu concentrations of 0-5-1-5 mug/ml medium. Between concentrations of 5 and 40 mug Cu/ml medium, lengths and wet-weights of cartilage cultures decreased significantly (P less than 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 less than 0-001). 3. With 5--20 mug 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 (EC 3.1.3.1) 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 7-5 mug/ml medium, lengths and wet-weights of cartilaginous cultures were significantly increased (P less than 0-001). As Zn concentrations were further increased (from 10 to 40 mug/ml medium), lengths and wet-weights were significantly decreased (P less than 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.
D000818:Animals; D001842:Bone and Bones / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology*; D002356:Cartilage / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology*; D002642:Chick Embryo; D003300:Copper / Q000172:deficiency / Q000494:pharmacology*; D046508:Culture Techniques; D004305:Dose-Response Relationship, Drug; D005269:Femur; D006651:Histocytochemistry; D013977:Tibia; D015032:Zinc / Q000172:deficiency / Q000494:pharmacology*
D003300:Copper; D015032:Zinc