ABSTRACT
OBJECTIVE: We have previously demonstrated the efficient and time-dependent transvascular localization of Sialyl Lewis X (SLX)-liposomes to inflammatory sites, but the final target of the SLX-liposomes remained uncertain. The aim of this study was to identify the target cells of the liposomes within the inflamed joints of collagen antibody-induced arthritis (CAIA) model mice. METHODS: SLX-liposomes and unlabeled liposomes encapsulating high-density colloidal gold were administered intravenously into the caudal vein of CAIA mice on day 5 after induction of arthritis when the inflammatory score was maximal (n = 6 per group). Six hours or 24 h after liposome administration, animals were euthanized and hind limbs and ankles were excised without perfusion. After fixation, synovial tissues were examined by light microscopy after silver enhancement of colloidal gold or by transmission electron microscopy. RESULTS: Silver-enhanced signals were detected within the cells around E-selectin-positive blood vessels in the synovium of the SLX-liposome group. These cells were positive for the macrophage/monocyte marker F4/80 or neutrophil marker Ly-6G. Transmission electron microscopy detected the colloidal gold signals together with liposome-like structures within the phagosomes of synovial macrophages. Transmission electron microscopy and energy dispersive X-ray spectrometry could determine gold elements in the lysosomes of synovial macrophages. CONCLUSIONS: The results of the current study demonstrate that SLX-liposomes primarily targeting E-selectin in activated endothelial cells could potentially deliver their contents into inflammatory cells around synovial blood vessels in arthritic joints.
Subject(s)
Arthritis, Experimental/metabolism , E-Selectin/metabolism , Foot Joints/metabolism , Gold Colloid/administration & dosage , Macrophages/metabolism , Animals , Arthritis, Experimental/pathology , Foot Joints/pathology , Foot Joints/ultrastructure , Knee Joint/metabolism , Knee Joint/pathology , Knee Joint/ultrastructure , Liposomes , Lysosomes/metabolism , Lysosomes/ultrastructure , Macrophages/ultrastructure , Mice , Mice, Inbred DBA , Microscopy/methods , Microscopy, Electron, Transmission , Oligosaccharides/metabolism , Sialyl Lewis X AntigenABSTRACT
Free radical stress leads to tissue injury and progression of disease conditions such as arthritis, hemorrhagic shock, atherosclerosis, diabetes, hepatic injury, aging and ischemia, reperfusion injury of many tissues, gastritis, tumor promotion, neurodegenerative diseases and carcinogenesis. Safer anti-oxidants suitable for long term use are needed to prevent or stop the progression of free radical mediated disorders. Herbal medicine provides a foundation for various traditional medicine systems worldwide. The Sida species is one of the most important families of medicinal plants in India. Hence, the present study was aimed to investigate the possible anti-oxidant potential of Sida rhombifolia extracts for 30 days on adjuvant induced arthritis in experimental rats. The altered levels of hematological parameters were reverted to near normal levels, especially the elevated rate of erythrocyte sedimentation was significantly reduced by S. rhombifolia extracts in experimental rats. Oral administration of root and stem of S. rhombifolia extracts significantly increased the levels of thiobarbituric acid reactive substances and activities of catalase and glutathione peroxidase and decreased the levels of reduced glutathione and superoxide dismutase activity in arthritis induced rats. The free radical scavenging activity of the plant was further evidenced by histological and transmission electron microscopy observations made on the hind limb tissue.
