Expression and ultrastructural localization of Mint2 in the spinal cord of rats.

Mint protein family, as adaptor molecules, contains three members, Mint1, Mint2 and Mint3. Although Mint3 is ubiquitously expressed, Mint1 and Mint2 have been reported to express specifically in neuron. Here we demonstrated Mint1 and Mint2 expression pattern in rat spinal cord. The protein level of Mint2 was found to be higher than that of Mint1 in rat spinal by western blot. In an attempt to know Mint2 distribution in the spinal cord of rat, in situ hybridization was carried out, Mint2 mRNA was showed to be ubiquitously distributed in cervical, thoracic and lumbar sections of rat spinal cord, and high intensive signal was detected in motor neurons. These were further confirmed by fluorescent immunohistochemistry, Mint2 was also found to exist throughout gray matter especially motor neurons where Mint2 was mainly located in perikaryon, however, Mint1 was showed to be relatively lower. By electron microscope, Mint2 was found to be mainly located in vesicles in perikaryon in motor neuron of lumbar section, and at the same time Mint2 was located in axons in myelin and presynaptic terminals. These data suggest that Mint2 may play more important role in spinal cord than the other two family members.

Survivin is involved in the anti-apoptotic effect of edaravone in PC12 cells.

Edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one), a newly developed hydroxy radical scavaging agent which has been widely used for protection against ischemia-reperfusion injury is highly effective in preventing cell apoptosis. However, the exact intracellular mechanism(s) underlying the protective action of edaravone is not clear. We observed that in PC12 cells cultured under serum deprivation (DEPV) condition, the levels of survivin were positively correlated with the anti-apoptotic action of edaravone. Survivin RNA interference (RNAi) increased DEPV-induced PC12 cell apoptosis, whereas the anti-apoptotic effect of edaravone was blunted by survivin RNAi. Moreover, survivin overexpression provided protection against DEPV-induced PC12 cell apoptosis. Inhibition of ERK and PI(3)-K/AKT prevented edaravone's ability to decrease apoptosis and increase survivin. In conclusion, the present study provides the first direct evidence that survivin involves in the anti-apoptotic effects of edaravone via a pathway involving ERK and PI(3)-K/AKT.

Transplanted bone marrow stromal cells improve cognitive dysfunction due to aging hypoperfusion in rats.

BACKGROUND: Aging is an important risk factor for vascular dementia, and D-galactose (D-gal) injection can simulate the pathology of aging. Two-vessel occlusion of common carotid arteries (2VO) is the most popular model for vascular dementia. This study was aimed to investigate the possibility of D-gal injection plus 2VO simulating cognitive impairment of aging vascular dementia; and whether transplanted bone marrow stromal cells (BMSCs) can improve the cognitive function induced by D-gal injection plus 2VO. METHODS: Totally 30 male Sprague-Dawley rats were divided into 5 groups equivalently: control group, D-gal group, D-gal + 2VO group, D-gal + 2VO + saline water group, and D-gal + 2VO + BMSCs group. Aging hypoperfusion rats were created by subcutaneous injection of D-gal and occlusion of two common carotid arteries. BMSCs or saline water was stereotactically transplanted into the subventricular zone as treatment vehicles at 24 hours post operation. Two-way repeat analysis of variance (ANOVA) was used for significance analysis of 5 groups at 6 weeks post transplantation; moreover, Tamhane's test (equal variance not assumed) and least significant difference (LSD) test (equal variance assumed) were used for pairwise comparison in Morris water maze (MWM). RESULTS: Transplanted BMSCs distributed around the lateral ventricles and acquired the phenotypes of neurons and astrocytes. In terms of swimming path distance and escape latency in MWM, D-gal + 2VO + BMSC group showed significant improvement than the D-gal + 2VO group but was still obviously worse than the control group (both P < 0.05). There was no significant difference in swimming speed for all 5 groups. CONCLUSIONS: D-gal plus 2VO induces cognitive dysfunction. The engrafted BMSCs exhibit the beneficial effect on cognitive function via promotion interactively with host brain.

Unilateral amyloid-beta25-35 injection into the rat amygdala increases the expressions of aberrant tau phosphorylation kinases.

BACKGROUND: Neuropathologically, Alzheimer disease (AD) is characterized by the presence of extracellular plaques enriched in beta-amyloid peptides; however, the mechanism by which it results in the neurotoxicity is uncertain. The purpose of this study was to investigate whether it would prompt the progress of Alzheimer disease via enhancement of aberrant phosphorylated tau that results from its increased kinase gene expression. METHODS: Twenty-four male rats were divided into three groups, and each group had 8 rats: control, sham-operated, and Abeta(25-35) injected AD model groups. AD rat models were created by unilateral injections of Abeta(25-35) into the amygdala. The hyperphosphorylated tau protein was estimated by immunohistochemistry with paired helical filament-1 (PHF-1) antibody and paired helical filament-tau (AT8) antibody. The expressions of glycogen synthase kinase-3beta (GSK-3beta) and p38 mitogen-activated protein kinase (P(38)MAPK) mRNA were observed by in situ hybridization. RESULTS: Compared with the control and sham-operated groups, the evaluation of paired AT8 and paired helical filament-1 (PHF-1) in the cortexes and hippocampus of the AD model group showed the numbers of AT8 and PHF-1 positive cells, as well as the optical density (OD) values of the proteins were significantly higher (AT8: in CA2: 0.318 +/- 0.037 vs. 0.135 +/- 0.028, 0.136 +/- 0.031; in frontal cortex: 0.278 +/- 0.040 vs. 0.130 +/- 0.028, 0.190 +/- 0.037. PHF-1: in CA2: 0.386 +/- 0.034 vs. 0.139 +/- 0.010, 0.193 +/- 0.041; in frontal cortex: 0.395 +/- 0.050 vs. 0.159 +/- 0.030, 0.190 +/- 0.044, respectively, P < 0.01); the number of GSK-3beta mRNA and P(38)MAPK mRNA positive cells of the AD model group, as well as the OD values, also increased significantly in the cortexes, hippocampus (GSK-3beta-mRNA: in CA2: 0.384 +/- 0.012 vs. 0.190 +/- 0.015, 0.258 +/- 0.064; in frontal cortex: 0.398 +/- 0.018 vs. 0.184 +/- 0.031, 0.218 +/- 0.049. P(38)MAPK mRNA: in CA2: 0.409 +/- 0.038 vs. 0.161 +/- 0.041, 0.189 +/- 0.035; in frontal cortex: 0.423 +/- 0.070 vs. 0.160 +/- 0.032, 0.203 +/- 0.053, respectively, P < 0.01). CONCLUSION: Unilateral injection of Abeta(25-35) into the rat amygdala increases the generation of aberrant phosphorylated tau by increasing GSK-3beta and P(38)MAPK gene expression, that accelerates the process of Alzhemer's disease.