Ginsenoside Rd maintains adult neural stem cell proliferation during lead-impaired neurogenesis

Abstract

Lead exposure attracts a great deal of public attention due to its harmful effects on human health. Even low-level lead (Pb) exposure reduces the capacity for neurogenesis. It is well known that microglia-mediated neurotoxicity can impair neurogenesis. Despite this, few in vivo studies have been conducted to understand the relationship between acute Pb exposure and microglial activation. We investigated whether the acute Pb exposure altered the expression of a marker of activated microglial cells (Iba-1), and markers of neurogenesis (BrdU and doublecortin) in aging rats. As compared to controls, Pb exposure significantly enhanced the expression of Iba-1 immunoreactivity; increased the expression levels of IL-1β, IL-6, and TNF-α and decreased the numbers of BrdU(+) and doublecortin(+) cells. Our prior work demonstrated that ginsenoside Rd (Rd), one of the major active ingredients in Panax ginseng, was neuroprotective in a variety of paradigms involving anti-inflammatory mechanisms. Thus, we further examined whether Rd could attenuate Pb-induced phenotypes. Compared with the Pb exposure group, Rd pretreatment indeed attenuated the effects of Pb exposure. These results suggest that Rd may be neuroprotective in old rats following acute Pb exposure, which involves limitation of microglial activation and maintenance of NSC proliferation.

Ginseng Extract G115 Attenuates Ethanol-Induced Depression in Mice by Increasing Brain BDNF Levels

“…The regional-specific effects of antidepressants on brain BDNF levels were previously reported [ 24 , 25 , 32 ]. The increase of neurogenesis in the hippocampus is one of the neuroprotective mechanisms of ginsenoside Rg1 and Rd [ 19 , 33 , 34 ]. Therefore, the prominent effect of G115 in the hippocampus might involve neurogenesis.…”

Protective effects of ginseng on neurological disorders

“…In addition, Rg1 promoted neural stem cell differentiation through the cyclic adenosine monophosphate-protein kinase A (cAMP-PKA) and PI3K-AKT signaling pathways (Jiang et al, 2012a ; Li et al, 2013 ). Ginsenoside Rd also increased neural stem cell proliferation (Lin et al, 2012b ) and maintained neurogenesis after lead-induced neural injury (Wang et al, 2013b ). Panax notoginseng saponins decreased the expression of the neurite inhibitory molecules Nogo-A and NgR after cerebral ischemia in rats, suggesting a role in axonal regeneration after injury (Liu et al, 2014 ).…”

The effects of the Panax Vietnamensis ethanol fraction on proliferation and differentiation of mouse neural stem cells

“…Previous studies on Panax vietnamensis extract already presented its new ginsenosides and other bioactive substances 10,41 as well as its in vivo effects on the nervous system 22 . Others already pointed out positive effects of Panax ginseng extract/ginsenosides on nervous system in vivo of increasing SOX2 expression and promoting hippocampal proliferation 14,42 , attenuating neural stem cell scenescence 43 , maintaining neural stem cell proliferation in lead poisoning 44 . Because neural stem/progenitor cells still reside in the body, many questions concerning specific mechanisms of ginseng extract/ginsenosides still remain.…”