Intranasal ginsenoside Rb1 protects pentylenetetrazole-induced epileptic mice

OBJECTIVE To evaluate whether ginsenoside Rb1 has antiepileptic effects on pentylenetetrazole（PTZ）-induced epileptic mice via intranasal therapeutic administration. METHODS Rb1 monoclonal antibody was used to observe the distribution of Rb1 20 mg · kg;in mouse brain tissues under different administration routes and to explore the feasibility of intranasal Rb1. PTZ was injected intraperitoneally into healthy ICR mice every 48 hours to construct a tonic-clonic epileptic model. Then Rb1 20 or 40 mg · kg;or valproate 300 mg · kg;or saline was administered intranasally for 30 d, and PTZ was continued every five days to imitate occasional convulsions in the clinic. Racine scale（RCS） and wireless electroencephalogram（EEG）monitoring were used to assess the presence and severity of seizure. Immunofluorescence（IF） was performed after drug treatment to evaluate the effect of Rb1 on brain neuron, microglia and astrocyte in epileptic mice. RESULTS Rb1 had specific binding with anti-Rb1 in the brain under different administration routes, and intranasal Rb1 was able to enter the brain and play a therapeutic role（P<0.01）. PTZ-injured mice presented body mass loss, higher seizure stage and shorter seizure latency. At the same time, epileptic waves, mainly spikes, were detected by wireless EEG. Compared with PTZ group, intranasal Rb1 increased mice weight（P<0.01） and seizure latency（P<0.05）, reduced seizure stage（P<0.01）and EEG spikes. In addition, Rb1 significantly reduced neuron loss（P<0.01） indicated by NeuN staining and decreased the number of activated microglia（P<0.01） indicated by Iba-1 staining in the cortex and CA1 area of hippocampus. Moreover, Rb1 reduced the decrease of GLT-1 and GS expression（P<0.05） induced by PTZ. CONCLUTION Intranasal Rb1 has anti-epileptic effects on PTZ mice. Moreover, Intranasal Rb1 affects the functions of neurons, astrocytes and microglia through regulating the expression of GLT and GS in astrocytes, which may be related to its anti-epileptic effect.