Cilostazol/ginkgo-biloba

Renexin, a compound of cilostazol and ginkgo biloba extract, has been reported to produce neuroprotective effects through antioxidant, antiplatelet, and vasodilatory mechanisms. This study was designed to investigate the protective effects of renexin on hearing, the organ of Corti (OC), and medial olivocochlear efferents against noise-induced damage. C57BL/6 mice were exposed to 110 dB SPL white noise for 60 min and then randomly divided into three groups: high- and low-dose renexin-treated groups and noise only group. Renexin were administered for 7 days: 90 mg/kg to the low-dose, and 180 mg/kg to the high-dose groups. All mice, including the controls underwent hearing tests on postnoise day 8 and were killed for cochlear harvest. We compared the hearing thresholds and morphology of the OC and cochlear efferents across the groups. The renexin-treated groups recovered from the immediate threshold shifts in a dose-dependent manner, while the noise group showed a permanent hearing loss. The renexin-treated ears demonstrated less degeneration of the OC. The diameters of the efferent terminals labeled with α-synuclein were preserved in the high-dose renexin-treated group. In the western blot assay of the cochlear homogenates, the treated groups displayed stronger expressions of α-synuclein than the noise and control groups, which may indicate that noise-induced enhanced activity of the cochlear efferent system was protected by renexin. Our results suggest that pharmacologic treatment with renexin is hopeful to reduce or prevent noise-induced hearing loss as a rescue regimen after noise exposure.

White-matter (WM) lesions are known to potentiate cognitive impairment in poststroke patients. The present study was designed to assess whether Ginkgo biloba extract (GB) and cilostazol, which were evaluated alone and in a combination formula (Renexin), can attenuate the WM lesions and cognitive decline caused by chronic hypoperfusion in the rat.

ANIMALS WERE DIVIDED INTO FIVE TREATMENT GROUPS: cilostazol (25 mg/kg/day), GB (20 mg/kg/day), Renexin (25 mg/kg/day cilostazol + 20 mg/kg/day GB), vehicle, and sham. The animals received the treatments orally 1 day after bilateral common carotid artery occlusion [two-vessel occlusion (2VO); except for the sham group, which underwent the surgery but the arteries were not occluded], and then the same dose every day for 21 days thereafter. Prior to sacrificing the rats, repetitive eight-arm radial maze testing was performed to examine their cognitive abilities. After drug administration and cognitive testing, brain tissues were isolated for Klüver-Barrera and terminal deoxynucleotidyl transferase-mediated biotin-dUTP nick end-labeling (TUNEL) staining, immunohistochemical assessment of glial fibrillary acidic protein (GFAP) and CD11b (OX-42), and to assay free-radical scavenging activity.

We found that the significant WM lesions induced by 2VO was ameliorated significantly by treatment with cilostazol, GB, and Renexin, in association with increased TUNEL-positive cells. In addition, chronic cerebral hypoperfusion caused a large increase in the degree of GFAP and OX-42 immunoreactivity and free-radical activity in the optic tract. These abnormalities were significantly reversed by the three drugs, but most prominently by Renexin, suggesting a markedly enhanced or supra-additive effect of cilostazol and GB when administered together.

Significant attenuation of cytoarchitectural damage and apoptotic cell death was found with GB and cilostazol, but a markedly enhanced effect was seen for treatment with their combination in the WM of rat brains after bilateral occlusion of the common carotid arteries. We suggest that combination therapy with GB and cilostazol provides enhanced neuroprotective effects and induces subsequent cognitive improvement in patients with chronic ischemic conditions.