Severity dependent up-regulations of LOX-1 and MCP-1 in early sclerotic changes of common carotid arteries in spontaneously hypertensive rats.

Lectin-like oxidized low-density lipoprotein receptor (LOX-1) and monocyte chemoattractant protein-1 (MCP-1) are molecules involving in the initiation and progression of atherosclerosis. In order to examine a possible difference in LOX-1 and MCP-1 expressions depending on the severity of early stage of atherosclerosis, we investigated atherosclerotic changes by exposure to hypertension and hyperlipidemia in common carotid arteries (CCAs) of stroke-prone spontaneously hypertensive rat (SHR-SP). Three rat model groups such as control [Wistar Kyoto rat (WKY) group], hypertension (SHR-SP group) and hypertension + hyperlipidemia [SHR-SP + high fat and cholesterol (HFC) group] were used. Body weights, brain weights, systolic blood pressures and serum levels of total cholesterol, low-density lipoprotein and triglyceride were measured at 0, 5, 10 and 15 days after appropriate diet. Immunohistochemistry showed that the positive area and the strength of LOX-1 and MCP-1 were larger in the SHR-SP + HFC group than in the SHR-SP group, while no immunoreactivities were found in the WKY group. Conventional RT-PCR and real-time PCR analyses showed that mRNAs of those in the SHR-SP group were higher with greater up-regulation in the SHR-SP + HFC group. LOX-1 and MCP-1 expressions were coordinately up-regulated at mRNA and protein levels in an early stage of sclerosis depending on the severity of atherosclerotic stress. Activations of LOX-1 and MCP-1 are collectively involved in the early stage of atherosclerosis.

Functional improvement by electro-acupuncture after transient middle cerebral artery occlusion in rats.

Functional recovery by the application of electro-acupuncture (EA) on different acupoints was investigated using a transient middle cerebral artery occlusion (MCAO) model in rat. Acupoints were Baihui (D20) plus Renzhong (D26) (MCAO + D group), and Hanyan (G4), Xuanlu (G5), Xuanli (G6), plus Qubin (G7) (MCAP + G group). Animals with EA treatment showed significant functional improvements from 12 days after the reperfusion against those without EA treatment. Among EA treated groups, MCAO + G showed a more significant recovery than MCAO + D. Infarct volume revealed the significant reduction in the EA treated groups especially in MCAO + G at 30 days. Immunohistochemical study showed a remarkable induction of vascular endothelial growth factor (VEGF) in astrocytes of the peri-infarct area at 30 days, more in EA treated groups than in groups treated with MCAO alone. These results suggest that the acupoints applied in this study are effective for the functional recovery, and an enhanced expression of VEGF may play a certain role in recovery process after stroke.

Targeting of post-ischemic cerebral endothelium in rat by liposomes bearing polyethylene glycol-coupled transferrin.

To achieve an efficient delivery targeting to post-ischemic cerebral vascular endothelium, PEG-liposome conjugated with transferrin (Tf) (Tf-PEG-liposome) was intravenously administered to the rats after 90 min of transient middle cerebral occlusion. The expression of Tf receptor (TfR) in the cerebral endothelium increased with a peak at 1 day after the reperfusion and returned to the control level by 6 days. The Tf-PEG fluorescence was marginally detectable in sham control brain, but remarkably increased with a peak at 2 days, showing about 70% of TfR positive vascular endothelium double-labeled with Tf-PEG. These results indicate that the Tf-PEG-liposome could be utilized as an efficient drug delivery tool to the brain after stroke.

Enhanced phosphorylation of PTEN in rat brain after transient middle cerebral artery occlusion.

A phosphatase PTEN (phosphatase and tensin homologue deleted on chromosome 10) is a tumor suppressor gene that suppresses cell growth, inhibits cell migration, and induces apoptosis. Phosphorylated form of PTEN (p-PTEN) is a key survival factor relating PI3K-Akt pathway and their downstream effectors. A spatiotemporal profiles of PTEN and p-PTEN expression were immunohistochemically examined after 90 min of transient middle cerebral artery occlusion in rats. In the ischemic core, PTEN progressively decreased by 3 days, whereas a rapid but transient increase of p-PTEN was found with a peak at 1 h after the reperfusion. In contrast, in the ischemic penumbra, PTEN showed a minor change and a gradual but sustained p-PTEN expression was observed in the ischemic penumbra with a peak at 12 h. In addition, the balance of population among strongly, moderately, and weakly stained cells was different between the ischemic core and penumbra at their peak time points. These results suggest an important role of p-PTEN for cell survival after ischemia as an upstream regulator for PI3K-Akt.

Enhanced expression of phospho-Akt by electro-acupuncture in normal rat brain.

Electro-acupuncture (EA) is an effective curative method for various diseases in oriental medicine. To investigate a detailed molecular mechanism of EA stimulation, an induction of phospho-Akt (p-Akt) was examined in normal adult rat brain after 60 min of EA with acupoints of Baihui (D20) and Renzhong (D26). In the sham control brain, strong neuronal p-Akt expression was found in ventral posterolateral thalamic nucleus (VPL) and medial habenular nuclei (MHb), but moderate to weak in cortex, caudate, CA1 sector and dentate gyrus of hippocampus, and ventral posteromedial thalamic nucleus. EA stimulation generally enhanced and sustained p-Akt expression for at least 24 h especially in the regions listed above, except VPL and MHb where no apparent change was found. Western blot analysis of p-Akt confirmed the enhanced signal intensity after EA at 8 and 24 h. These results suggest that the EA on D20 and D26 acupoints activates the survival Akt signal pathway, which may be maintaining the neural functions such as cell survival and memory formation in normal brain.