CORM-3, a carbon monoxide-releasing molecule, alters the inflammatory response and reduces brain damage in a rat model of hemorrhagic stroke

OBJECTIVE: Intracerebral hemorrhage is accompanied by a pronounced inflammatory response that mediates brain damage but is also essential for the tissue reparative process. We assessed the effect of CORM-3, a water-soluble carbon monoxide-releasing molecule possessing anti-inflammatory properties, on inflammation and brain injury after intracerebral hemorrhage.

DESIGN: In vivo and in vitro laboratory study.

SETTING: Research laboratory.

SUBJECTS: Male Sprague-Dawley rats, 250-350 g.

INTERVENTIONS: A model of collagenase injection (2 μL) in the brain was established to induce intracerebral hemorrhage. CORM-3 (4 or 8 mg/kg) was administered intravenously at different times as follows: 1) 5 mins before collagenase; 2) 3 hrs after collagenase; and 3) 3 days after collagenase challenge.

MEASUREMENTS AND MAIN RESULTS: Saline was used as a negative control. Brain damage, brain water content, and behavioral assessment were evaluated. The inflammatory response was determined at set intervals after intracerebral hemorrhage by counting peripheral neutrophils and lymphocytes, neutrophils, and activated microglia/macrophages in the intracerebral hemorrhage area and measuring plasma tumor necrosis factor-á levels. BV2 microglia and DI-TNC1 astrocytes were exposed to triton (1%) or CORM-3 (10-100 ìM) and cytotoxicity (lactic dehydrogenase assay) measured at 24 hrs. A challenge with collagenase to induce intracerebral hemorrhage caused marked brain damage and modified the levels of inflammatory markers. Pretreatment with CORM-3 significantly prevented injury, modulated inflammation, and reduced plasma tumor necrosis factor-α. CORM-3 given 3 hrs after collagenase significantly increased brain injury and tumor necrosis factor-α production. In contrast, CORM-3 given 3 days after collagenase afforded partial protection, modulated inflammation, and decreased tumor necrosis factor-α starting from the day of application. No dose-dependent effects were observed.

CONCLUSIONS: CORM-3 promotes neuroprotection or neurotoxicity after intracerebral hemorrhage depending on the time of administration. Beneficial effects are achieved when CORM-3 is given either before or 3 days after intracerebral hemorrhage, namely, as a prophylactic agent or during the postacute inflammatory phase.