phenanthrenes and Spinal-Cord-Diseases

Spinal cord injury (SCI) remains a source of morbidity after thoracoabdominal aortic reconstruction. These studies were designed to determine whether PJ34, a novel ultrapotent inhibitor of the nuclear enzyme poly(adenosine diphosphate ribose) polymerase (PARP) could modulate neurologic injury after thoracic aortic ischemia reperfusion (TAR) in a murine model of SCI.. Forty-one anesthetized male mice were subject to thoracic aortic occlusion (11 minutes) through a cervical mediastinotomy followed by 48 hours of reperfusion (TAR) under normothermic conditions. PJ34-treated mice (PJ, n = 12) were given 10 mg/kg PJ34 intraperitoneally 1 hour before ischemia and 1 hour after unclamping. The control group (UN, n = 21) received normal saline intraperitoneally 1 hour before ischemia and 1 hour after unclamping. Sham animals (n = 10) were subject to thoracic aortic exposure with no aortic clamping and similar intraperitoneal normal saline injections. PARP-1-/- (KO, n = 8) mice were subjected to the same conditions as the UN mice. Blinded observers rated murine neurologic status after TAR by using an established rodent paralysis scoring system. Murine spinal cords were subjected to cytokine (GRO-1) protein analysis as a marker of inflammation and immunohistochemical analysis (hematoxylin-eosin and PAR staining). Paralysis scores (PS) and GRO-1 levels were compared with analysis of variance, and survival data were compared with chi 2 .. Immediately after TAR, UN and PJ mice had severe neurologic dysfunction (PS = 5.8 +/- 0.1 and 4.6 +/- 0.6, respectively; P > .05), which was significantly worse than the KO mice (PS = 1.0 +/- 0.7, P < .001). After 6, 24, and 48 hours KO mice had no discernable neurologic injury (PS = 0). Six hours after TAR, PJ mice significantly improved (PS = 1.1 +/- 0.73, P < .001) and remained improved at 24 (PS = 0.7 +/- 0.6) and 48 hours (PS = 0.6 +/- 0.6). UN mice did not improve their PS, and Sham mice showed no neurologic abnormality at any time during these experiments. The mortality at 48 hours was 0% for PJ and KO mice, 43% for UN (P = .012), and 0% for Sham. GRO-1 levels were significantly decreased in PJ and KO versus UN mice (UN, 583 +/- 119 vs PJ, 5.8 +/- 0 vs KO, 5.3 +/- 1.4 mg/pg; P < .0001). Immunohistochemistry showed evidence of decreased PAR staining and ventral motor neuron injury in PJ mice.. Genetic deletion of PARP or inhibition of its activity (PJ34) rescued neurologic function in mice subjected to TAR. PARP inhibition might represent a novel therapeutic approach for prevention of SCI after TAR.

Topics: Animals; Aorta, Abdominal; Aorta, Thoracic; Immunohistochemistry; Injections, Intraperitoneal; Male; Mice; Motor Neurons; Phenanthrenes; Poly Adenosine Diphosphate Ribose; Poly(ADP-ribose) Polymerase Inhibitors; Protozoan Proteins; Reperfusion Injury; Spinal Cord; Spinal Cord Diseases

Poly(ADP-ribose) polymerase (PARP) activity has been implicated in the pathogenesis of several central nervous system (CNS) disorders. For example, the presence of extensive poly(ADP)ribosylation in CNS tissues from animals with experimental allergic encephalomyelitis (EAE) indicates that PARP activity may be involved in this inflammatory disease process. Using PJ34 [N-(6-oxo-5,6-dihydrophenanthridin-2-yl)-N, N-dimethylacetamide.HCl], a selective PARP inhibitor, we studied the mechanisms through which PARP activity may contribute to the onset of acute EAE. PLSJL mice immunized with myelin antigens were treated with PJ34, and the effects on the progression of EAE and several other parameters relevant to the disease process were assessed. PJ34 exerted therapeutic effects at the onset of EAE that were associated with reduced CNS inflammation and the maintenance of neurovascular integrity. Expression of genes encoding the intercellular adhesion molecule-1 (ICAM-1) and the inflammatory mediators interferon-gamma, tumor necrosis factor-alpha, and inducible nitric-oxide synthase were decreased in CNS tissues from drug-treated animals. Administration of PJ34 biased the class of myelin basic protein (MBP)-specific antibodies elicited from IgG2a to IgG1 and IgG2b and modulated antigen-specific T-cell reactivity. Therefore, the mode of action of PJ34 at the onset of EAE is likely mediated by a shift in the MBP-specific immune response from a proinflammatory Th1 toward an anti-inflammatory Th2 phenotype.

Topics: Adjuvants, Immunologic; Animals; Blood-Brain Barrier; Disease Models, Animal; Encephalomyelitis, Autoimmune, Experimental; Intercellular Adhesion Molecule-1; Mice; Myelin Basic Protein; Phenanthrenes; Poly(ADP-ribose) Polymerase Inhibitors; Spinal Cord Diseases; T-Lymphocytes; Th2 Cells; Tumor Necrosis Factor-alpha