atractyloside and Brain-Ischemia

Cannabinoid type 1 (CB1) receptor agonist arachidonyl-2-chloroethylamide (ACEA) induces neuroprotection against brain ischemia, and the mechanism, however, is still elusive. In this study, we used bilateral common carotid artery occlusion (BCCAO) in mice and oxygen-glucose deprivation (OGD) in primary cultured neurons to mimic brain ischemic injury, and hypothesized that cannabinoid CB1 receptor agonist ACEA protects ischemic neurons via inhibiting the opening of mitochondrial permeability transition pore (MPTP). In vivo, we found that BCCAO treatment reduced the neurological functions, increased the number of apoptotic neuronal cells and deteriorated the mitochondrial morphology in the ischemic brain tissue. And in vitro, we observed that OGD injury reduced cell viability, mitochondrial function and anti-oxidant SOD2 expression, increased lactate dehydrogenase (LDH), mitochondrial cytochrome C (Cyto C) and apoptosis-inducing factor (AIF) releases, elevated the cell apoptosis and mitochondrial superoxide level. And the CB1 receptor agonist ACEA significantly abolished the BCCAO and OGD-induced neuronal injury above. However, the MPTP opener atractyloside (Atr) markedly reversed the ACEA-induced neuroprotective effects, inhibited the mitochondrial Cyto C and AIF releases and relieved the mitochondrial swelling, but the MPTP inhibitor cyclosporin A (CsA) did not cause significant effects on the ACEA-induced neuroprotection above. These findings indicated that inhibition of MPTP opening may be involved in the cannabinoid CB1 receptor agonist ACEA-induced neuroprotection.

Topics: Animals; Apoptosis; Apoptosis Inducing Factor; Arachidonic Acids; Atractyloside; Brain Ischemia; Cell Survival; Cyclosporine; Cytochromes c; L-Lactate Dehydrogenase; Male; Mice; Mitochondrial Membrane Transport Proteins; Mitochondrial Permeability Transition Pore; Neuroprotective Agents; Primary Cell Culture; Superoxide Dismutase; Superoxides

Ischemic postconditioning (IPost) has been shown to attenuate cerebral ischemia-reperfusion injury. However, the mechanism remains elusive. Because opening of the mitochondrial permeability transition pore (MPTP) is a crucial determinant of cell death after ischemia-reperfusion, we hypothesized that the neuroprotective effect of IPost may be associated with inhibition of MPTP opening. In part 1 of this study, pentobarbital-anesthetized rats subjected to middle cerebral artery occlusion for 90 min, followed by reperfusion for 72 h, were assigned to receive one of the following treatments: three cycles of IPost (15s each), intracerebroventricular injection of saline (control), administration of the MPTP inhibitor cyclosporin A (CsA) (2 μmol/L, 15 μL) or its vehicle alcohol, administration of the MPTP opener atractyloside (Atr) (2 mmol/L, 15 μL), or IPost plus CsA/Atr treatment. Neurological deficit scores (NDS) and infarct volumes were assessed. Mitochondrial ultrastructure and swelling were also examined after reperfusion. In part 2, control and IPost groups underwent ischemia (90 min) and reperfusion (15 min). CsA and Atr groups were treated as described in part 1. Brain mitochondria were isolated after reperfusion and MPTP activity was evaluated. IPost or CsA treatment significantly improved NDS and reduced infarction volume, while Atr reversed the neuroprotective effects of IPost, and attenuated the decrease in mitochondrial swelling induced by IPost or CsA. Thus, inhibiting MPTP opening may play a crucial role in the neuroprotective effects of IPost, which may have potential clinical value against cerebral ischemia-reperfusion injury.

Topics: Animals; Atractyloside; Brain Ischemia; Cyclosporine; Ischemic Postconditioning; Male; Microscopy, Electron, Transmission; Mitochondria; Mitochondrial Membrane Transport Proteins; Mitochondrial Permeability Transition Pore; Random Allocation; Rats; Rats, Sprague-Dawley

The present study evaluated the potential neuroprotective effect and underlying mechanism of the total flavones extracted from Chrysanthemum morifolium (TFCM) against ischemia/reperfusion (I/R) injury. An animal model of cerebral ischemia was established by occluding the right middle cerebral artery for 90 minutes followed by reperfusion for 22 hours. The neurobehavioral scores, infarct area, and hemispheric edema were evaluated. The superoxide dismutase (SOD) activity, malondialdehyde (MDA) content, and reactive oxygen species (ROS) level in brain were also measured. The results showed that pretreatment with TFCM significantly decreased the neurological deficit scores, percentage of infarction, and brain edema and attenuated the decrease in SOD activity, the elevation of MDA content, and the generation of ROS. In isolated brain mitochondria, Ca(2+)-induced swelling was attenuated by pretreatment with TFCM, and this effect was antagonized by atractyloside. These results showed that pretreatment with TFCM provides significant protection against cerebral I/R injury in rats by, at least in part, its antioxidant action and consequent inhibition of mitochondrial swelling.

Topics: Animals; Antioxidants; Atractyloside; Brain; Brain Ischemia; Calcium; Cerebral Infarction; Chrysanthemum; Edema; Flowers; Male; Malondialdehyde; Nervous System Diseases; Phytotherapy; Plant Extracts; Rats; Rats, Sprague-Dawley; Reactive Oxygen Species; Reperfusion Injury; Superoxide Dismutase