ginsenoside-rg3 and Brain-Ischemia

Ginseng has been used worldwide as traditional medicine for thousands of years, and ginsenosides have been proved to be the main active components for their various pharmacological activities. Based on their structures, ginsenosides can be divided into ginseng diol-type A and ginseng triol-type B with different pharmacological effects. In this study, six ginsenosides, namely ginsenoside Rb1, Rh2, Rg3, Rg5 as diol-type ginseng saponins, and Rg1 and Re as triol-type ginseng saponins, which were reported to be effective for ischemia-reperfusion (I/R) treatment, were chosen to compare their protective effects on cerebral I/R injury, and their mechanisms were studied by in vitro and in vivo experiments. It was found that all ginsenosides could reduce reactive oxygen species (ROS), inhibit apoptosis and increase mitochondrial membrane potential in cobalt chloride-induced (CoCl₂-induced) PC12 cells injury model, and they could reduce cerebral infarction volume, brain neurological dysfunction of I/R rats in vivo. The results of immunohistochemistry and western blot showed that the expression of Toll-like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88), silencing information regulator (SIRT1) and nuclear transcription factor P65 (NF-κB) in hippocampal CA1 region of some ginsenoside groups were also reduced. In general, the effect on cerebral ischemia of Rb1 and Rg3 was significantly improved compared with the control group, and was the strongest among all the ginsenosides. The effect on SIRT1 activation of ginsenoside Rb1 and the inhibition effect of TLR4/MyD88 protein expression of ginsenoside Rb1 and Rg3 were significantly stronger than that of other groups. The results indicated that ginsenoside Rg1, Rb1, Rh2, Rg3, Rg5 and Re were effective in protecting the brain against ischemic injury, and ginsenoside Rb1 and Rg3 have the strongest therapeutic activities in all the tested ginsenosides. Their neuroprotective mechanism is associated with TLR4/MyD88 and SIRT1 activation signaling pathways, and they can reduce cerebral ischemic injury by inhibiting NF-κB transcriptional activity and the expression of proinflammatory cytokines, including interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6).

Topics: Animals; Brain Ischemia; CA1 Region, Hippocampal; Cobalt; Ginsenosides; Male; Myeloid Differentiation Factor 88; Neuroprotective Agents; NF-kappa B; Panax; PC12 Cells; Rats; Rats, Sprague-Dawley; Reactive Oxygen Species; Reperfusion Injury; Sirtuin 1; Toll-Like Receptor 4

This study was conducted to investigate the neuroprotective effects of 20(S)-ginsenoside Rg3 on focal cerebral ischemia in rats. Middle cerebral artery occlusion (MCAO) model in male Wistar-Kyoto (WKY) rats was employed. The behavioral tests were used to evaluate the damage to central nervous system. The infarct area of brain was assessed in the brain slices stained with 2,3,5-triphenyltetrazolium chloride (TTC). Hydrogen clearance techniques were used to monitor regional cerebral blood flow (rCBF), spectrophotometric assay methods were used to determine the activities of superoxide dismutase (SOD) and glutathione-peroxidase (GSH-Px), contents of malondialdehyde (MDA) and adenosine triphosphate (ATP) of the brain. Furthermore, the respiratory control ratio (RCR=State 3/State 4) was assessed in the brain mitochondria. The results showed that sublingual vein injection of 20(S)-ginsenoside Rg3 at doses of 10 and 5 mg kg(-1), but not 2.5 mg kg(-1) exhibited significant neuroprotective effects on rats against focal cerebral ischemic injury by markedly decreasing neurological deficit scores, reducing the infarct area and enhancing the rCBF compared with the control group. At the same time, 20(S)-ginsenoside Rg3 significantly improved mitochondrial energy metabolism, antagonized decreases in SOD and GSH-Px activities and increase in MDA level induced by cerebral ischemia. All these findings suggest that 20(S)-ginsenoside Rg3 might provide neuroprotection against the cerebral ischemia-induced injury in rat brain through reducing lipid peroxides, scavenging free radicals and improving the energy metabolism.

Topics: Adenosine Triphosphate; Analysis of Variance; Animals; Brain Chemistry; Brain Ischemia; Calcium Channel Blockers; Cerebral Infarction; Disease Models, Animal; Dose-Response Relationship, Drug; Ginsenosides; Glutathione Peroxidase; Infarction, Middle Cerebral Artery; Male; Malondialdehyde; Mitochondria; Neurologic Examination; Neuroprotective Agents; Nimodipine; Rats; Rats, Inbred WKY; Superoxide Dismutase; Time Factors