[Protective Effect of Ginsenoside Rg3 on Lipopolysaccharide-Induced Neuronal-Galial Interaction Injury Model]

To investigate the protective effect of ginsenoside Rg3 on lipopolysaccharide-induced galial-neuronal interaction injury model.

Primary microglia cells and HT-22 cell lines were cultured, and the cells were divided into the control group (CON), the 100 ng/mL LPS group (LPS), the control inflammation model group (CM), the ginsenoside Rg3 group, and the inflammation model plus ginsenoside Rg3 treatment group (CM+Rg3). Ginsenoside Rg3 was administered in the ginsenoside Rg3 group and the CM+Rg3 group at the doses of 2.5, 5, 10, and 20 μmol/L. Galial-neuronal interaction modeling was performed in the CM group and the CM+Rg3 group. The purity of the primary microglia cells was assessed by immunofluorescence, the viability of the HT-22 cells in each group was assessed by CCK-8, and changes in the levels of inflammatory cytokines, including interleukin (IL)-1β, IL-6, tumor necrosis factor α (TNF-α), and IL-10, in the cell samples of each group were assessed with the ELISA kits. The level of cellular oxidative damage was measured with a ROS kit, and the expression of apoptosis-related proteins, including Bax and Bcl-2, was assessed by Western blot. The activity of Caspase-3 enzyme in each group was measured with a Caspase-3 enzyme activity kit.

The purity of the microglia cultured reached over 95% and was suitable for subsequent experiments. After ginsenoside Rg3 stimulation at different doses, the survival rate of HT-22 was not much different from that of the CON group. The survival rate of neurons after 100 ng/mL LPS stimulation was 98%, indicating that Rg3 and LPS had no effect on the survival of neurons. Compared with that of the CON group, the survival rate of HT-22 cells in the CM group was significantly decreased (P<0.01). Compared with the CM group, the CM+Rg3 group showed a significant increase in the viability of neurons (P<0.01), indicating that the glia-neuron interaction model was successfully constructed. When Rg3 dose was 10 μmol/L, the HT-22 cells in CM+Rg3 group showed the highest viability (P<0.05). Hence, 10 μmol/L Rg3 was selected for further experiments. After 100 ng/mL LPS stimulation, the concentrations of IL-1β, IL-6, TNF-α, and IL-10 in HT-22 cells were not significantly different from those in the CON group. After 100 ng/mL LPS stimulation, the concentrations of IL-1β and TNF-α in microglia were higher than those in the CON group (P<0.05), but the concentrations of IL-1β and TNF-α in the LPS+Rg3 group were lower than those in the LPS group (P<0.05). The concentration of reactive oxygen species in the CM+Rg3 group was slightly higher than that in the CON group, and significantly lower than that in the CM group (P<0.01). The expression of Bax in the CM+Rg3 group was higher than that in the CON group, and lower than that in the CM group. The expression of Bcl-2 was lower in the CON group, and higher than that in the CM group (P<0.01). The Caspase-3 enzyme activity in the CM group was significantly higher than that in the CON group (P<0.01). The Caspase-3 enzyme activity in the CM+Rg3 group was significantly lower than that in the CM group (P<0.01).

Ginsenoside Rg3 may play a role in the alleviation of neuronal apoptosis by regulating glial cell damage, reducing the secretion of inflammatory factors, and inhibiting neuronal apoptosis.