METHODS: The cytotoxic effect of 6-shogaol was determined by 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The neuritogenic activity was assessed by neurite outgrowth stimulation assay while the concentration of extracellular NGF in cell culture supernatant was assessed by enzyme-linked immunosorbent assay (ELISA). Involvement of cellular signaling pathways, mitogen-activated protein kinase kinase/extracellular signal-regulated kinase1/2 (MEK/ERK1/2) and phosphoinositide-3-kinase/protein kinase B (PI3K/AKT) in 6-shogaol-stimulated neuritogenesis were examined by using specific pharmacological inhibitors.
RESULTS: 6-Shogaol (500 ng/ml) induced neuritogenesis that was comparable to NGF (50 ng/ml) and was not cytotoxic towards PC-12 cells. 6-Shogaol induced low level of NGF biosynthesis in PC-12 cells, showing that 6-shogaol stimulated neuritogenesis possibly by inducing NGF biosynthesis, and also acting as a substitute for NGF (NGF mimic) in PC-12 cells. The inhibitors of Trk receptor (K252a), MEK/ERK1/2 (U0126 and PD98059) and PI3K/AKT (LY294002) attenuated the neuritogenic activity of both NGF and 6-shogaol, respectively.
CONCLUSIONS: The present findings demonstrated that 6-shogaol induced neuritogenic activity in PC-12 cells via the activation MEK/ERK1/2 and PI3K/AKT signaling pathways. This study suggests that 6-shogaol could act as an NGF mimic, which may be beneficial for preventive and therapeutic uses in neurodegenerative diseases.
MATERIALS AND METHODS: The study was designed as quasiexperimental with a control group that only received posttests. We performed in vivo study with an induction bilateral common carotid artery occlusion (BCCAO) model and vitamin D injection for 10 days. A total of 24 rats were divided into four groups (n = 6): Sham operation (SO [control]), BCCAO (transient global cerebral ischemic model not given vitamin D), VD1 (BCCAO + vitamin D 0.125 μg/kgBW), and VD2 (BCCAO + vitamin D 0.5 μg/kgBW). The spatial memory function was tested with the Morris water maze. We performed immunohistochemistry to localise p16 expression. p16, p21 and NGF mRNA expression were assessed by reverse transcriptase (RT-PCR) method.
RESULTS: The vitamin D treatment group required shorter mileage to find the platform and probe test. The total time spent was longer in the target quadrant than in non-target. The Vitamin D-treated group had lower p16 and p21 mRNA expression and higher NGF mRNA expression than the BCCAO group. Immunostaining showed p16 signal in the pyramidal cell of CA1 area in the BCCAO group.
CONCLUSION: Vitamin D repairs memory function, senescence expression was lower and NGF was higher in the BCCAO model.
METHODS: Thirty-eight female Sprague-Dawley rats were divided into three groups: mesh, sham (no mesh), and control. Urodynamic study and NGF analysis of the urogenital tissues were done and results were compared among all groups. The urodynamic studies of the mesh and sham groups were further divided into the 4th and 10th days. A P-value