Cryptotanshinone protects against oxidative stress in the paraquat-induced Parkinson's disease model.

Parkinson's disease (PD) is a common neurodegenerative disorder associated with striatal dopaminergic neuronal loss in the Substantia nigra. Oxidative stress plays a significant role in several neurodegenerative diseases. Paraquat (PQ) is considered a potential neurotoxin that affects the brain leading to the death of dopaminergic neurons mimicking the PD phenotype. Various scientific reports have proven that cryptotanshinone possesses antioxidant and anti-inflammatory properties. We hypothesized that cryptotanshinone could extend its neuroprotective activity by exerting antioxidant effects. This study was designed to evaluate the effects of cryptotanshinone in both cellular and animal models of PQ-induced PD. Annexin V-PI double staining and immunoblotting were used to detect apoptosis and oxidative stress proteins, respectively. Reactive oxygen species kits were used to evaluate oxidative stress in cells. For in vivo studies, 18 B6 mice were divided into three groups. The rotarod data revealed the motor function and immunostaining showed the survival of TH+ neurons in SNpc region. Our study showed that cryptotanshinone attenuated paraquat-induced oxidative stress by upregulating anti-oxidant markers in vitro, and restored behavioral deficits and survival of dopaminergic neurons in vivo, demonstrating its therapeutic potential.

Vitamin B3 Provides Neuroprotection via Antioxidative Stress in a Rat Model of Anterior Ischemic Optic Neuropathy.

Supplementing with vitamin B3 has been reported to protect against retinal ganglion cell (RGC) damage events and exhibit multiple neuroprotective properties in a mouse model of optic nerve injury. In this study, a rat model of anterior ischemic optic neuropathy was used to assess the neuroprotective benefits of vitamin B3 (rAION). Vitamin B3 (500 mg/kg/day) or phosphate-buffered saline (PBS) was administered to the rAION-induced rats every day for 28 days. The vitamin B3-treated group had significantly higher first positive and second negative peak (P1-N2) amplitudes of flash visual-evoked potentials and RGC densities than the PBS-treated group (p < 0.05). A terminal deoxynucleotidyl transferase dUTP nick end labeling assay conducted on vitamin B3-treated rats revealed a significant reduction in apoptotic cells (p < 0.05). Superoxide dismutase and thiobarbituric acid reactive substance activity showed that vitamin B3 treatment decreased reactive oxygen species (p < 0.05). Therefore, vitamin B3 supplementation preserves vision in rAION-induced rats by reducing oxidative stress, neuroinflammation, and mitochondrial apoptosis.

Long term therapeutic effects of icariin-loaded PLGA microspheres in an experimental model of optic nerve ischemia via modulation of CEBP-ß/G-CSF/noncanonical NF-κB axis.

An ischemic insult at optic nerve (ON) is followed by detrimental neuroinflammation that results in progressive and long-lasting retinal ganglion cell (RGC) death and vision loss. Icariin was reported to be a safe and effective natural anti-inflammatory drug. Herein, we evaluated the long-term therapeutic effects of a single intravitreal injection of poly(lactide-co-glycolide) PLGA-icariin in a rat model of anterior ischemic optic neuropathy (rAION). Treatment with PLGA microspheres of icariin preserved the visual function and RGC density for 1 month in the rAION model. In addition, ON edema and macrophage infiltration were inhibited by treating PLGA microspheres of icariin. We found that the binding complex of icariin and CCAAT enhancer binding protein beta (CEBP-ß) significantly induced endogenous granulocyte colony-stimulating factor (G-CSF) expression to activate noncanonical nuclear factor kappa B (NF-κB) signaling pathway by promoting an alternative phosphorylation reaction of IKK-ß. Activation of noncanonical NF-κB signaling pathway promoted the M2 microglia/macrophage polarization and AKT1 activation, which prevented neuroinflammation and RGC apoptosis after ON infarct. This study concluded that protective mechanism of icariin is a CEBP-ß/G-CSF axis-induced noncanonical NF-κB activation, which provides the long-term neuroprotective effects via anti-inflammatory and antiapoptotic actions after ON ischemia.

Intravitreal Injection of Long-Acting Pegylated Granulocyte Colony-Stimulating Factor Provides Neuroprotective Effects via Antioxidant Response in a Rat Model of Traumatic Optic Neuropathy.

Traumatic optic neuropathy (TON) may cause severe visual loss following direct or indirect head trauma which may result in optic nerve injuries and therefore contribute to the subsequent loss of retinal ganglion cells by inflammatory mediators and reactive oxygen species (ROS). Granulocyte colony-stimulating factor (G-CSF) provides the anti-inflammatory and anti-oxidative actions but has a short half-life and also induces leukocytosis upon typical systemic administration. The purpose of the present study was to investigate the relationship between the anti-oxidative response and neuroprotective effects of long-acting pegylated human G-CSF (PEG-G-CSF) in a rat model of optic nerve crush (ONC). Adult male Wistar rats (150-180 g) were chosen to have a sham operation in one eye and have ONC in the other. PEG-G-CSF or phosphate-buffered saline (PBS control) was immediately administered after ONC by intravitreal injection (IVI). We found the IVI of PEG-G-CSF does not induce systemic leukocytosis, but increases survival of RGCs and preserves the visual function after ONC. TUNEL assays showed fewer apoptotic cells in the retina in the PEG-G-CSF-treated eyes. The number of sorely ED1-positive cells was attenuated at the lesion site in the PEG-G-CSF-treated eyes. Immunoblotting showed up-regulation of p-Akt1, Nrf2, Sirt3, and HO-1 in the ON of the PEG-G-CSF-treated eyes. Our results demonstrated that one IVI of long-acting PEG-G-CSF is neuroprotective in the rONC. PEG-G-CSF activates the p-Akt1/Nrf2/Sirt3 and the p-Akt1/Nrf2/HO-1 axes to provide the antioxidative action and further attenuated RGC apoptosis and neuroinflammation. This provides crucial preclinical information for the development of alternative therapy with IVI of PEG-G-CSF in TON.