Role of polymorphs in inflammatory cartilage destruction in adjuvant arthritis of rats.

The inflammatory destruction of cartilage in rat adjuvant arthritis has been studied by histochemistry and autoradiography. Naphthol-AS-D-chloroacetate esterase has been used as a marker for polymorphs. The evidence presented here shows that polymorphs accumulate at the cartilage-pannus border and in areas of cartilage loss. These cells appear therefore to be of decisive importance for the destruction of cartilage. Proteoglycans were demonstrated by safranin-O staining: there is a loss of PG that is particularly prominent in zones where pannus had invaded cartilage. By means of 35S labelling of proteoglycans it was possible to show that pannus containing polymorphs can invade living cartilage.