Canine bone marrow cell cultures infected with canine distemper virus: an in vitro model of Paget's disease.

We have previously shown that the canine paramyxovirus, canine distemper virus (CDV), is a possible aetiologic agent in Paget's disease of bone and in the canine bone disorder, metaphyseal osteopathy. More recently, we have examined the effects of CDV on the formation of multinucleated, tartrate resistant acid phosphatase positive, calcitonin receptor positive, osteoclast-like cells in cultures of canine bone marrow mononuclear cells, and shown that both in vitro and in vivo infection with CDV produced a dose dependent increase in the number and size of osteoclast-like cells. We have now extended these results to show that CDV infection induces interleukin-6 and c-Fos mRNA in these cells, similar to our recent findings in pagetic bone cells. These results further support the hypothesis that CDV might be involved in the aetiopathogenesis of Paget's disease and metaphyseal osteopathy and suggest that canine marrow culture systems will prove useful as an in vitro model to examine the disease processes in more detail.