The effect of Mycoplasma arthritidis infection on the phagocytic activity of macrophages in rats and mice

Abstract

Summary The phagocytic activity of mononuclear phagocytes of A/J mice and Wistar rats was estimated by the carbon clearance test following injection of Mycoplasma arthritidis. In mice, the overall phagocytic activity was significantly increased at the end of the first week (P < 0.0001), but the increase was marginal by the third and fourth weeks after injection. A significant increase in the relative weight of liver and spleen was observed even when phagocytic activity had returned to levels similar to those of controls (P < 0.001). In rats, the overall phagocytic activity was significantly increased until the fourth week (P < 0.00001). There was not, however, an increase in the relative weight of liver and spleen as observed for the mice. The results are discussed in the context of factors contributing to the pathogenic mechanisms responsible for differences in the patterns of arthritis due to mycoplasma observed in mice and rats.

The effect of Mycoplasma arthritidis infection on the kinetics of colloidal carbon clearance in mice

“…The graph of carbon concentration in blood against time showed that between time 0 and 3 min elimination of carbon from the blood was accelerated. Since this accelerated early phase of clearance is due to several factors other than phagocytosis, attachment of carbon particles to platelets and macrophage surface membranes [12], the K values between 3 and 30 min were used in the analyses [13]. The K index, which is conceptually identical and numerically equivalent to the partial regression coefficient, for every animal was calculated and analysed by standard co-variance analysis with K as dependent variable and concentration at 3 min post-injection and treatment procedures as independent variables [14].…”

The effect ofMycoplasma arthritidisinfection on the kinetics of colloidal carbon clearance in mice

“…Since this accelerated early phase of clearance is due to several factors other than phagocytosis, attachment of carbon particles to platelets and macrophage surface membranes [12], the K values between 3 and 30 min were used in the analyses [13]. The K index, which is conceptually identical and numerically equivalent to the partial regression coefficient, for every animal was calculated and analysed by standard co-variance analysis with K as dependent variable and concentration at 3 min post-injection and treatment procedures as independent variables [14].…”

“…Intravenous inoculation of M. arthritidis into male A/J mice had a biphasic effect on the phagocytic activity of the MPS assessed by the carbon clearance test in which colloidal carbon is selectively accumulated in Kuppfer ceils of the liver and the macrophages of the red pulp of the spleen [13]. From 4-12 h after inoculation, phagocytic activity was significantly depressed, with the K values falling below the standard deviation.…”