Yandong Zhou

Wayne State University, Detroit, Michigan, United States

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Publications (4)12.2 Total impact

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    ABSTRACT: The effect that exercise has on angiogenesis in the aging rat is unknown. We initiated this study with the intent to determine if exercise could induce angiogenesis in aging rats, as well as in adult rats reported previously. The markers we used to determine our endpoint were vascular endothelial growth factor (VEGF) and angiopoietin 1 and 2, as well as vascular density. Aged (22 month old) female Fisher 344 rats (n=16) were exercised on a treadmill 30 minutes each day for 3 weeks, or housed as non-exercised controls for the same duration. At the end of the exercise protocol, a significant (p<0.01) increase in the density of microvessels was found within the cerebral vasculature of the rats. Exercise was also associated with a significantly (p<0.01) increased mRNA expression of angiopoietin 1 and 2 in the aged cohort of rats. A mild but significant (p<0.01) increase in the four isoforms of VEGF mRNA (120, 144, 164, 188) were observed, with VEGF120 and VEGF144 being more markedly up-regulated than the other two. VEGF protein expression was also significantly (p<0.01) increased. This study demonstrates that angiogenesis can be induced in aging rats via exercise. The induced angiogenesis was associated with overexpression of angiogenic factors. These results support the hypothesis that an angiogenic response to chronic physical exercise is maintained with aging.
    Current Neurovascular Research 02/2006; 3(1):15-23. · 2.84 Impact Factor
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    ABSTRACT: The poor quality of life after a stroke is largely attributed to deficits in cognitive-motor functioning. The goals of this study were to detect if damaged motor learning function were attributed to motor deficits in rats following a transient middle cerebral artery (MCA) occlusion. Stroke was induced by a 2-h occlusion of the MCA using an intraluminal filament. Motor functions were evaluated from 5 up to 28 days after reperfusion in ischemic and control rats. Motor function was detected by a series of motor tests (runway traversing and beam balancing, as well as foot fault placing, parallel bar crossing, rope and ladder climbing), and motor learning behavior was determined by analyzing the rate of improvement of impaired function during performance of the motor tasks. Significant (P<0.001) motor deficits were detected in the stroke group (n=10) while performing motor tasks that involve extensive coordination, in comparison to the controls (n=12). Although motor behavior was improved with repeated behavior testing, unparalleled rate of improvement of motor performance on rope and ladder climbing tests was found between the two groups, suggesting an impaired motor learning function. Brain tissue damage was detected in the ischemic animals 28 days after surgery, demonstrated by 40% infarct volume of contralateral hemisphere. Both motor learning and motor function were impaired in ischemic rats. The motor tests used in this study are sensitive, semi-quantitative, and reproducible measurements of functional impairment in rats following an ischemic stroke.
    Behavioural Brain Research 04/2002; 132(1):29-36. · 3.33 Impact Factor
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    ABSTRACT: In ischemic stroke, the ischemic crisis activates a cascade of traumatic events that are potentiated by reperfusion and eventually lead to neuronal degeneration. The primary aim of this study was to investigate a procedure that could minimize this damage by interfering with the interactions between reestablished blood flow and ischemically damaged tissue, as well as by improving regional microcirculation. Using a novel hollow filament, the authors flushed the ischemic territory with heparinized saline before vascular reperfusion after occlusion of the middle cerebral artery (MCA). The results demonstrate a statistically significant (p < 0.001) reduction in infarct volume (75%; from 45.3 +/- 3.6% to 11.4 +/- 1.7%, determined with Nissl staining) in rats in which a 2-hour MCA occlusion was followed by a 48-hour reperfusion. Infarction and neuronal degeneration were confirmed using silver staining, which revealed a significantly larger infarct (36.3%, p < 0.05) than that detected with Nissl staining. The long-term neuroprotection of the prereperfusion flushing was also evaluated. This was determined by a series of motor behavior tasks (foot placing, parallel bar traversing, rope and ladder climbing) performed up to 28 days after reperfusion. Motor deficits were found to be significantly ameliorated in animals that underwent the flushing procedure (p < 0.001). In addition, neurological outcome was also improved significantly (p < 0.001) in the same animals. These results indicate that interaction between reperfusion and the metabolically and biochemically compromised tissue could be interrupted by the prereperfusion flushing procedure, which could lead to a reduction in brain injury from stroke. Mechanical reopening of the cerebral occlusion with local flushing and isolated reperfusion of the regionally injured brain might offer new treatment options for patients with stroke.
    Journal of Neurosurgery 03/2002; 96(2):310-9. · 3.15 Impact Factor
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    ABSTRACT: Poly(ADP-ribose) polymerase (PARP) can initiate an energy-consuming and inefficient repair cycle following cerebral ischemia/reperfusion by transferring ADP ribose units to nuclear proteins eventually leading to cellular dysfunction and neuronal death. 3-Aminobenzamide (3-AB) is a selective inhibitor of PARP that can significantly reduce brain damage after focal ischemia in rats and displays a low toxicity in vivo. The goals of this study were to determine if inhibiting PARP with 3-AB has a long-term neuroprotective effect and if functional outcome improves in rats following focal ischemia and treatment with 3-AB. Focal ischemia was induced by a 2-h occlusion of the middle cerebral artery (MCA), using an intraluminal filament. Motor functions were evaluated from 5 to 28 days after reperfusion in four groups of rats: stroke without treatment; stroke treated with 3-AB at doses of 15 mg/kg, stroke treated with 3-AB at doses of 55 mg/kg; and the non-ischemic control rats. Functional behaviors were tested by a series of motor function tasks (foot placing, parallel bar crossing, rope and ladder climbing), as well as a neurological examination. Infarct volume of stroke brain in the same rat was determined by Nissl staining 28 days after surgery. Comparison of the untreated stroke group (n=11) and the treated stroke groups indicates that impairment of motor function was significantly (P<0.001) reduced by administration of 3-AB at doses of 15 mg/kg (n=9) or 55 mg/kg (n=10). Neurological outcome was also improved significantly (P<0.001). Infarct volume was significantly (P<0.01) reduced in both treated groups. Long-term neuroprotection following ischemia/reperfusion injury to the brain can be obtained by administration of a PARP inhibitor. The motor tests employed in this study can be used as sensitive, objective and reproducible measurements of functional impairment in rats following an ischemic stroke.
    Brain Research 10/2001; · 2.88 Impact Factor