ABSTRACT
OBJECTIVE: To evaluate the role of synovial oxidative stress on joint pathology in a spontaneous mouse model of osteoarthritis (OA) by intra-articular (IA) delivery of recombinant adeno-associated virus (rAAV) expressing anti-oxidant protein heme oxygenase-1 (HO-1). METHODS: Joint transduction by rAAV vectors was evaluated with serotype 1, 2, 5 and 8 capsids carrying LacZ gene administered by IA injections into STR/ort mice. Transduced cell types were identified by ß-galactosidase staining in sectioned joints. Effect of oxidative stress on AAV transduction of primary synoviocytes in vitro was quantitated by fluorescence-activated cell sorting (FACS) analysis. In vivo, the efficacy of rAAV1/HO-1 was tested by IA administration into STR/ort mice followed by histopathological scoring of cartilage. Levels of 3-nitrotyrosine (3-NT) and HO-1 were assessed by immunohistochemistry (IHC) of joint sections. RESULTS: Administration of a rAAV1 based vector into OA mouse joints resulted in transduction of the synovium, joint capsule, adipocytes and skeletal muscle while none of the serotypes showed significant cartilage transduction. All OA joints exhibited significantly elevated levels of oxidative stress marker, 3-NT, in the synovium compared to OA-resistant CBA-strain of mice. In vitro studies demonstrated that AAV transgene expression in primary synoviocytes was augmented by oxidative stress induced by H(2)O(2) and that a rAAV expressing HO-1 reduced the levels of oxidative stress. In vivo, HO-1 was increased in the synovium of STR/ort mice. However, delivery of rAAV1/HO-1 into OA joints did not reduce cartilage degradation. CONCLUSIONS: AAV-mediated HO-1 delivery into OA joints during active disease was not sufficient to improve cartilage pathology in this model.
Subject(s)
Dependovirus/genetics , Gene Transfer Techniques , Heme Oxygenase-1/genetics , Joints/metabolism , Membrane Proteins/genetics , Osteoarthritis/metabolism , Oxidative Stress/physiology , Synovial Membrane/metabolism , Animals , Bone Remodeling/drug effects , Bone Remodeling/physiology , Disease Models, Animal , Heme Oxygenase-1/metabolism , Hydrogen Peroxide/adverse effects , Hydrogen Peroxide/pharmacology , In Vitro Techniques , Injections, Intra-Articular , Joints/pathology , Male , Membrane Proteins/metabolism , Mice , Mice, Inbred CBA , Mice, Inbred Strains , Mice, Mutant Strains , Osteoarthritis/pathology , Oxidative Stress/drug effects , Synovial Membrane/pathology , Transduction, Genetic , Tyrosine/analogs & derivatives , Tyrosine/metabolismABSTRACT
Cytomegalovirus (CMV)-associated gastrointestinal masses have been reported in human acquired immune deficiency syndrome patients. This is the first report on CMV-associated gastrointestinal masses in simian immunodeficiency virus (SIV)-infected macaques. Two SIV-infected macaques presented at necropsy with multiple nodular or umbilicated masses within the gastrointestinal tract. In one animal, the masses were located throughout the gastrointestinal tract, whereas in the other, the masses were restricted to the proximal small intestine. Grossly, the masses were indistinguishable from those caused by neoplastic conditions such as lymphoma and, histologically, were composed of hyperplastic glandular tissue, dense neutrophilic infiltrates within the lamina propria, and multifocal proprial hemorrhage. Frequent cytomegalic cells with basophilic intranuclear inclusions were found in affected regions. Immunohistochemistry for CMV demonstrated frequent immunopositive cells within affected areas. Furthermore, immunohistochemistry for the proliferation marker Ki-67 demonstrated increased proliferation in hyperplastic glands and crypts. CMV should be considered a cause of discrete mass lesions in the gastrointestinal tract of SIV-infected macaques.
