Macrophage depletion with clodronate-containing liposomes affects the incidence and development of rheumatoid arthritis.

ABSTRACT

OBJECTIVE: This study investigated the effect of macrophage depletion with clodronate-containing liposomes (Clo-lip) on the incidence and development of rheumatoid arthritis (RA). METHODS: The effect of macrophage depletion with Clo-lip in the spleen was assessed by HE (haematoxylin and eosin) staining and immunohistochemistry (IHC). Thirty BALB/c mice were randomly divided into three groups, which were administered PBS-lip, Clo-lip, or normal saline. RA model mice were then created and the appearance of the paws was observed. Expression of CD68 by macrophages was examined by immunofluorescence on the 49th day. Forty-five RA model mice were created and randomly divided into three groups. The experiment group was administered Clo-lip at different timepoints. The degree of arthritis score was recorded during the administration. Histological features were detected by HE staining on the 84th day. RESULTS: Compared to controls, horseshoe-shaped nuclei and multi-core large cells were reduced in the experimental group (HE stain; p < 0.05). Brown tag-CD68 and tag-CD80 macrophages were fewer in the experimental group than in the control group (immunohistochemistry; p < 0.05). Furthermore, the degree of arthritis score in the experimental group was significantly decreased (p < 0.05). HE staining showed that there was no or less inflammatory cell infiltration in the articular cavity in mice in the experimental group, and that the percentage of CD68+ macrophage cells in synovial cells was significantly lower than in the control group (p < 0.05). CONCLUSION: Macrophage depletion with Clo-lip can affect the incidence and development of RA.