Immunohistochemical analysis of nucleotide excision repair factors XPA and XPB in adult rat brain.

To study the regional and cellular distribution of xeroderma pigmentosum group A and B (XPA and XPB) proteins, two nucleotide excision repair (NER) factors, in the mammalian brain we used immunohistochemistry and triple fluorescent immunostaining combined with confocal microscope scanning in brain slices of adult rat brain, including the cerebral cortex, striatum, substantia nigra compacta, ventral tegmental area, red nucleus, hippocampus, and cerebellum. Both XPA and XPB proteins were mainly expressed in neurons, because the XPA- or XPB-immunopositive cells were only costained with NeuN, a specific neuronal marker, but not with glial fibrillary acidic acid, a specific astrocyte marker, in the striatum. Furthermore, XPA- and XPB-positive staining were observed in the neuronal nuclei.

Bcl-2 enhances neurogenesis and inhibits apoptosis of newborn neurons in adult rat brain following a transient middle cerebral artery occlusion.

To determine whether Bcl-2 could influence adult neurogenesis and prevent apoptosis of newborn neurons, we injected Bcl-2 expressing plasmid into the lateral ventricle of rat brain immediately following a 30-min occlusion of the middle cerebral artery (MCAO). We found that Bcl-2 increased neural progenitor cells (BrdU+-DCX+) in the ipsilateral striatum, newborn immature neurons (BrdU+-Tuj-1+) and newborn mature neurons (BrdU+-MAP-2+) in the ipsilateral striatum and frontal cortex at 1 to 4 weeks following MCAO. Bcl-2 overexpression promoted development of newborn neurons into GABAergic and cholinergic neurons in the ipsilateral striatum.

Induction of Bcl-2 and Bax was related to hyperphosphorylation of tau and neuronal death induced by okadaic acid in rat brain.

Abnormal hyperphosphorylation of the cytoskeletal protein tau is a characteristic feature of neurodegeneration in Alzheimer's disease (AD) brain. Okadaic acid (OA), a protein phosphatase inhibitor, induces neuronal death and hyperphosphorylation of tau. In the present study using a model of microinjection of OA into rat frontal cortex, we aimed to investigate if OA-induced hyperphosphorylation of tau and neuronal death are related to the expression of Bcl-2, an apoptosis inhibitor, or Bax, an apoptosis inducer.

Induction of CRMP-4 in striatum of adult rat after transient brain ischemia.

Aim: To study the expression of collapsing response mediated protein-4 (CRMP-4) and nestin in the ischemic adult rat brain following transient brain ischemia.

Methods: Brain ischemia was induced by transient left middle cerebral artery occlusion (MCAO) for 60 min in adult rats. The expression of CRMP-4, nestin and bromodeoxyuridine (BrdU) was analyzed by immunohistochemical method.

Distribution of Flk-1 and Flt-1 receptors in neonatal and adult rat brains.

Double-fluorescence staining was combined with confocal laser scanning microscopy to localize fetal liver kinase-1 (Flk-1) and fms-like tyrosine kinase-1 (Flt-1) in the neonatal rat brain. The results showed that Flk-1 and Flt-1 immunostaining was observed in the cells with neuron-specific enolase, a neuronal marker, and with factor VIII (F VIII), an endothelium marker, but not in cells with glial fibrillary acidic protein (GFAP), a glial marker, of brain sections from rats on postnatal day 7 (P7). This indicates that both vascular endothelial growth factor (VEGF) receptors were distributed in the neurons and the vascular endothelium.

Role of vascular endothelial growth factor in neuronal DNA damage and repair in rat brain following a transient cerebral ischemia.

The antisense knockdown technique and confocal laser scanning microscopic analysis were used to elucidate vascular endothelial growth factor (VEGF) induction and its effect on DNA damage and repair in rat brain following a transient middle cerebral artery occlusion. Immunohistochemical study and in situ hybridization showed that the expression of VEGF and its mRNA was enhanced in the ischemic core and penumbra of ischemic brain. Western blot analysis further illustrated that VEGF induction was time-dependently changed in these areas.

[Okadaic acid induces the expression of glutamate transporter EAAT1 in the neurons of rat brain].

To study the relationship between tau hyperphosphorylation and the function of glutamate transporter okadaic acid (OA), a protein phosphatase inhibitor, 20 ng in a 0.5 microl volume, was injected into the frontal cortex of rat brain and immunostaining was used to observe the phosphorylation of tau protein and the expression of excitatory amino acid transporter 1 (EAAT1) in the brain following the injection. The results showed that (1) the neurons in the center of the injection region displayed cytoplasmic shrinkage, swelling, nuclear pyknosis, and dislocation at the early stage, and necrosis appeared 3 d after the injection.

Neuroprotection by melatonin against ischemic neuronal injury associated with modulation of DNA damage and repair in the rat following a transient cerebral ischemia.

In the present study, double fluorescence staining combined with confocal laser scanning microscopy analysis were used to examine the effects of melatonin on ischemia-induced neuronal DNA strand breaks and its possible mechanisms in a transient middle cerebral artery (MCA) occlusion model. Results showed that melatonin dose-dependently reduced infarct areas and decreased both DNA double and single strand breaks (DSB and SSB) and enhanced cell viability in the peri-ischemic brain regions. Furthermore, Bcl-2 induction in the ischemic brain was further enhanced by melatonin treatment.