The effects of zinc deprivation on the host response to intramuscular bone matrix implants in the rat

Sterile sequentially extracted insoluble bone matrix gelatin and freeze-dried allogeneic demineralized whole bone matrix was implanted into a lumbar muscle pouch of 12 Sprague-Dawley rats fed a diet containing 0.9 ppm zinc and into 6 rats fed a diet containing 50 ppm zinc. Histological sections and microradiography demonstrated that skeletal tissue induction occurred in all instances. In the zinc-supplemented hosts, four weeks postimplantation, trabecular bone and bone marrow grew on both sides of the matrix implant which had been almost completely resorbed by matrixclast activity. However, in the zinc-deficient hosts, the central cavity of the matrix was first filled with mesenchyme and then cartilage cells which grew in the form of thin wedges into the implanted matrix. Poor vascularization appears to be an important factor in cell proliferation and abnormal differentiation in zinc deficiency.