Gadolinium chloride removes pulmonary intravascular macrophages and curtails the degree of ovine lentivirus-induced lymphoid interstitial pneumonia.
Ovine lentivirus (OvLV), a retrovirus, causes lymphoid interstitial pneumonia (LIP) in sheep. Pulmonary alveolar macrophages are believed to play a central role in lung inflammation caused by this virus. The pulmonary intravascular macrophage (PIM), a recently identified inflammatory cell, is under active investigation for its role in lung pathology. Gadolinium chloride (GC), a rare earth lanthanide, has been used in in vivo studies to abrogate macrophage function to understand their role in tissue pathology. We treated mock- and OvLV-infected lambs with GC once a week for 34 weeks to investigate the implications of PIMs in the pathogenesis of LIP using light and electron microscopy. Repeated treatments with GC did not cause any apparent physiological abnormalities in the lambs. Light microscopy on tissue sections showed that GC reduced the number of PIMs in OvLV-infected and mock-infected lambs. Ultrastructural examination of lung tissues from GC-treated lambs revealed electron-dense deposits of GC-like material in endosomes and cytoplasm of PIMs. The majority of the PIMs in GC-treated lambs appeared damaged. Semi-quantitative histological evaluation showed amelioration of the extent of LIP in GC-treated OvLV-infected lambs compared to placebo-treated OvLV-infected lambs. This study stresses the effectiveness of GC in eliminating PIMs and suggests their involvement in the pathogenesis of OvLV-induced LIP. The results also strengthen the usefulness of GC as a tool to study in vivo function of cells such as PIMs that are difficult to isolate for in vitro studies.
Singh
B
B
Department of Veterinary Pathobiology, Texas A & M University Agricultural Experiment Station, San Angelo 76901, USA.
de la Concha-Bermejillo
A
A
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use*; D005682:Gadolinium / Q000627:therapeutic use*; D016180:Lentivirus Infections / Q000188:drug therapy / Q000473:pathology / Q000662:veterinary*; D017972:Lentiviruses, Ovine-Caprine; D008168:Lung / Q000648:ultrastructure; D017563:Lung Diseases, Interstitial / Q000188:drug therapy / Q000473:pathology / Q000662:veterinary*; D016676:Macrophages, Alveolar / Q000187:drug effects* / Q000648:ultrastructure; D008297:Male; D008854:Microscopy, Electron; D012756:Sheep; D012757:Sheep Diseases / Q000188:drug therapy* / Q000473:pathology
D000893:Anti-Inflammatory Agents; D005682:Gadolinium; C038958:gadolinium chloride