Experimental study of ginsenoside Rb1 on herpes simplex virus-1 infection for protecting nerves

Objective: To explore the action mechanism of ginsenoside Rb1 (GRb1) on protecting herpes simplex virus-1 (HSV-1) infected nerves by studying its inhibitory effects on abnormal changes of apoptosis and nerve growth factor (NGF) mRNA expression in HSV-1 infected human glioma cells U251.

Methods: The inhibitory effects of GRb1 on HSV-1 induced abnormal apoptosis of U251 cells were detected using MTT colorimetry and flow cytometry. The NGF mRNA expressions in different treatment groups were detected using semiquantitative RT-PCR.

Results: (1) In 400 microg/mL GRb1 + HSV-1 group, MTT value was higher than HSV-1 group at 24, 36, and 48 h after infection (P < 0.05). (2) Cytopathic effects (CPE) were observed in HSV-1 group at 36 h after infection. In 400 microg/mL GRb1 + HSV-1 group merges increased at 36 h after infection, but most cells were in normal shapes. (3) Results of flow cytometry showed that the cell apoptosis rate was lower in 400 microg/mL GRb1 + HSV-1 group than in the HSV-1 group at24 and 36 h after infection (P < 0.05). (4) Results of RT-PCR showed that in 400 microg/mL GRb1 + HSV-1 group, NGF mRNA expressions decreased at 6-12 h after infection (P < 0.05), but it increased at 24, 36, and 48 h after infection, and was obviously higher than that in the HSV-1 group (P < 0.05).

Conclusions: GRb1 at an appropriate concentration could inhibit abnormal cell apoptosis and changes of NGF mRNA expressions in HSV-1 infection. Therefore, we inferred that GRb1 could protect nerves possibly through up-regulating NGF mRNA expressions and inhibiting apoptosis.