Ginsenoside Rb1 attenuates mouse cerebral ischemia/reperfusion induced neurological impairments through modulation of microglial polarization.

Cerebral ischemia/reperfusion causes high disability, recurrence, and mortality. Ischemic stroke is a powerful stimulus that triggers significant microglia activation. Ginsenoside Rb1 (GS-Rb1) has been demonstrated to have neuroprotective effects in the central nervous system. In this study, the effects of GS-Rb1 against cerebral ischemia/reperfusion were explored. A mouse model of middle cerebral artery occlusion (MCAO) was used to mimic the cerebral ischemia/reperfusion. Mice in MCAO + GS-Rb1 groups received 5, 10, or 20 mg/kg GS-Rb1 through intraperitoneal injection. Modified neurological severity scoring (mNSS) showed neurological function, while the open field test tested the anxiety-like behaviors. Cognitive impairment was evaluated by Morris water maze. Protein levels were evaluated by ELISA and Western blot and mRNA levels were analyzed by qRT-PCR. When compared to the MCAO mice, mice in the MCAO + GS-Rb1 group had significantly lower mNSS scores and less brain water content. GS-Rb1 alleviated both cognitive impairment and anxiety and inhibited microglial activation in the cerebral ischemia/reperfusion model. GS-Rb1 enhanced M2-type microglia polarization while inhibiting M1-type microglia polarization. In summary, we observed that GS-Rb1 had neuro-protective effects in a cerebral ischemia/reperfusion mouse model through regulating the microglia polarization.