Abstract T P217: Neuroprotective Effects of Cilostazol through the Multi-mechanisms in Mice Permanent Focal Ischemia

Abstract

Background and Purpose: It has been reported that Cilostazol, which is phosphodiesterase (PDE) 3 inhibitor clinically used as an antiplatelet drug, could ameliorate ischemic brain injury, but the mechanisms were not clarified. We aimed to investigate how Cilostazol affected mice permanent focal ischemia model. Methods: Male Balb/c mice were subjected to permanent middle cerebral artery (MCA) occlusion. They were treated with Cilostazol (10- mg/kg or 20- mg/kg) or vehicle 30 min and 24 h post-ischemia. Infarct volume was assessed by 2,3,5-triphenyltetrazolium chloride (TTC) method after 48 h (n=8 in each group). In histological analysis, the animals were sacrificed 6 h or 24 h post-ischemia (n=5 in each group), and then the immunohistochemistry was performed to the brain sections. Results: We showed that the treatment with Cilostazol salvaged the tissue damage in the infarct rim in a dose-dependent manner, and 20- mg/kg Cilostazol significantly reduced infarct volume to 70.1±24.4% of the control (P<0.05). Immunoreaction for 8-Hydroxydeoxyguanosine (OHdG), an oxidative stress marker, showed the neuronal damage by oxidative stress in peri-infarct, and the treatment with Cilostazol reduced the ratio of the damaged neurons 6 h post-ischemia (65.8±33.5% in vehicle-treated animals, 21.3±9.9% in Cilostazol-treated ones, P<0.05). Double staining for 8-OHdG and von Willebrand factor also showed that Cilostazol attenuated oxidative stress on the endothelial cells in peri-infarct 24 h post-ischemia, significantly (P<0.01). On the other hand, the immunostaining for phosphorylated cAMP response element binding protein (pCREB) showed that Cilostazol increased the ratio of the pCREB-positive neurons in peri-infarct 24 h post-ischemia significantly (74.5±8.0% in vehicle-treated animals, 93.6±2.9% in Cilostazol-treated ones, P<0.01). Conclusions: These findings suggested that Cilostazol could have multi-mechanisms to ameliorate tissue damage due to permanent focal cerebral ischemia. Thus, one is to attenuate oxidative stress on neurnons and endothelial cells in the infarct rim, and another is to protect neural damage with anti-apoptotic effect through the pathway of Akt/pCREB.