Protective Effects of a Rhodiola Crenulata Extract and Salidroside on Hippocampal Neurogenesis against Streptozotocin-Induced Neural Injury in the Rat

Abstract

Previously we have demonstrated that a Rhodiola crenulata extract (RCE), containing a potent antioxidant salidroside, promotes neurogenesis in the hippocampus of depressive rats. The current study was designed to further investigate the protective effect of the RCE on neurogenesis in a rat model of Alzheimer's disease (AD) induced by an intracerebroventricular injection of streptozotocin (STZ), and to determine whether this neuroprotective effect is induced by the antioxidative activity of salidroside. Our results showed that pretreatment with the RCE significantly improved the impaired neurogenesis and simultaneously reduced the oxidative stress in the hippocampus of AD rats. In vitro studies revealed that (1) exposure of neural stem cells (NSCs) from the hippocampus to STZ strikingly increased intracellular reactive oxygen species (ROS) levels, induced cell death and perturbed cell proliferation and differentiation, (2) hydrogen peroxide induced similar cellular activities as STZ, (3) pre-incubation of STZ-treated NSCs with catalase, an antioxidant, suppressed all these cellular activities induced by STZ, and (4) likewise, pre-incubation of STZ-treated NSCs with salidroside, also an antioxidant, suppressed all these activities as catalase: reduction of ROS levels and NSC death with simultaneous increases in proliferation and differentiation. Our findings indicated that the RCE improved the impaired hippocampal neurogenesis in the rat model of AD through protecting NSCs by its main ingredient salidroside which scavenged intracellular ROS.

Effects of <i>Salidroside</i> on Cobalt Chloride-Induced Hypoxia Damage and mTOR Signaling Repression in PC12 Cells

“…44) Rapamycin can also increase the brain infarct size as well as increase the neurological deficit scores following focal cerebral ischemia in rats. 41) These studies suggest that the mTOR signaling pathway is involved in the underlying neuroprotective mechanisms during cerebral ischemia As increasing evidence suggests that SA may have neuroprotective effects in injured brain, [20][21][22] we speculate that SA may exert the neuroprotective effects by regulating the mTOR signaling pathway.…”

“…1a), has been documented to possess neuroprotective effects against neuronal damage induced by various insults. [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] However, the underlying mechanisms are still not well understood.…”

“…SA can reduce the degree of cerebral edema and the brain infarct size of rats with global cerebral ischemia, relieve the metabolism abnormity of free radicals and improve the function of cognition as well as behavioral and histological outcomes. [20][21][22] [23][24][25][26][27][28][29][30][31][32][33] In addition, it has been reported that SA may regulate mTOR signaling in cultured human umbilical vein endothelial cells (HUVECs) or in bladder cancer cell lines. 34,35) However, whether the neuroprotective effects of SA involve regulation of the mTOR signaling pathway in PC12 cells is still unknown.…”

Osthole Reverses Beta-Amyloid Peptide Cytotoxicity on Neural Cells by Enhancing Cyclic AMP Response Element-Binding Protein Phosphorylation

“…22) Cell Viability Assay The MTT assay was carried out as previously described. 23) Cells were plated in 96-well plates, and cell viability was determined using a conventional cytosine arabinoside, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT; Sigma) assay. After various incubations, cells were treated with the MTT solution (5 mg/ mL) at 37°C for 4 h in the dark.…”

Research on plant extracts and phytochemicals: criteria for evaluation

“…Examples are hepatotropic (Kheir Eldin et al 2008;Young et al 2007;Jain et al 2012;Eidi et al 2012;Ikewuchi et al 2011a, b;Godoy 2011), neurotropic (Qu et al 2012;van Thriel 2011) and nephrotropic (Venkatanarayana et al 2012) compounds, as well as antioxidative (Prachayasittikul et al 2009;Lee et al 2007 • Analytical data should be presented which characterize/ identify the material that has actually been tested.…”