Ginsenoside Rg3 attenuates neuroinflammation and hippocampal neuronal damage after traumatic brain injury in mice by inactivating the NF-kB pathway via SIRT1 activation

This investigation examined the potential of ginsenoside Rg3 in addressing traumatic brain injury (TBI). A TBI mouse model underwent treatment with ginsenoside Rg3 and nicotinamide (NAM). Neurological and motor functions were assessed using modified neurological severity score and rotarod tests. Brain water content in mice was detected. Primary mouse microglia were exposed to lipopolysaccharide (LPS), ginsenoside Rg3, and NAM. Nissl and immunofluorescence staining were utilized to investigate hippocampal damage, and localization of P65, Iba1 and INOS in microglia. Hippocampal neurons were grown in a culture medium derived from microglia. CCK-8 and TUNEL assays were employed to evaluate the viability and apoptosis of hippocampal neurons. Proinflammatory factors and proteins were tested using ELISA, western blot and immunofluorescence staining. As a result, ginsenoside Rg3 enhanced neurological and motor functions in mice post-TBI, reduced brain water content, alleviated hippocampal neuronal neuroinflammation and damage, activated SIRT1, and deactivated the NF-kB pathway. In LPS-stimulated microglia, ginsenoside Rg3 diminished inflammation, activated SIRT1, deactivated the NF-kB pathway, and facilitated nuclear localization of P65 and co-localization of Iba1 and INOS. The effects of ginsenoside Rg3 were countered by NAM in both TBI mice and LPS-stimulated microglia. Hippocampal neurons cultured in a medium containing LPS, ginsenoside Rg3, and NAM-treated microglia showed improved viability and reduced apoptosis compared to those cultured in a medium with LPS and ginsenoside Rg3-treated microglia alone. Ginsenoside Rg3 was effective in reducing neuroinflammation and damage in hippocampal neurons following TBI by modulating the SIRT1/NF-kB pathway, suggesting its potential as a therapeutic agent for TBI.