ABSTRACT
BACKGROUND:Researches showed that the enriched environment could improve the cognitive dysfunction of rats with vascular dementia. However, there are few reports regarding its mechanism of action. OBJECTIVE:To explore the effect of enriched environment on the cognitive dysfunction of rats with vascular dementia from the behavioral level. METHODS:Vascular dementia models weremade by permanent ligation of bilateral common carotid arteries and were divided into vascular dementia group (n=8) and enriched environment group (n=12). Vascular dementia group was taken care under conventional breeding environment for 30 days, while the enriched environment group was subjected to the enriched environment for 30 days. Morris water maze test was adapted to test the cognitive function of rats between two groups. Immunohistochemistry and immunoblotting were applied to observe the number ofDCX+cels and DCX protein level in both groups. The number of DCX-labeled cels co-expressing NeuN was observed using immunofluorescence technique. RESULTS AND CONCLUSION:(1) The escape latency in the vascular dementia group was longer than that in the enriched environment group (P< 0.05). The times across the platform was less in the vascular dementia group than that in the enriched environment group (P< 0.05). (2) In comparison with the enriched environment group, the number of DCX-positive cels andits protein level in the piriform cortex were significantly decreased in the vascular dementia group (P< 0.05). (3) The number of DCX/NeuN co-labeled cels in the piriform cortex was significantly less in the vascular dementia group than in the enriched environment group (P< 0.05). (4) These findings suggested that enriched environment could improve the cognitive dysfunction of rats with vascular dementia through promoting the expression and differentiation of the immature neurons.
ABSTRACT
BACKGROUND:Olfactory bulb neurogenesis, transformation and maturation have been considered the hot topic. Olfactory bulb experience and nervous activity can influence olfactory bulb neurogenesis. However, no study reports that olfactory bulb functions can affect olfactory bulb neurogenesis in guinea pigs. OBJECTIVE:To investigate the effect of unilateral olfactory functional deprivation on doublecortin, calbindin and parvalbumin expression in olfactory bulb of juvenile guinea pigs. METHODS:Total y 24 guinea pigs were randomly divided into two groups, which were kil ed after establishing olfactory functional deprivation model through electric cautery injury at the left peripheral nostrils. At 3 and 6 weeks after modeling, the specimens were harvested. The expression change of doublecortin, calbindin and parvalbumin in two sides’ olfactory bulb of juvenile guinea pigs was detected by immunohistochemistry. RESULTS AND CONCLUSION:The number of doublecortin, calbindin and parvalbumin positive cells in olfactory bulb at the un-deprived side was significantly higher than that at the deprived side at 3 and 6 weeks (P<0.05). This finding indicates that olfactory neural activities can affect neurogenesis and transformation in guinea pigs.
ABSTRACT
BACKGROUND: Present therapeutic tool cannot supplement infarct myocardium. Studies have shown that stem cell transplantation can promote regeneration of myocardium and vessels and improve heart function and prognosis.OBJECTIVE: To observe changes in morphology and hemodynamics in myocardium following embryonic stem cell transplantation in and surrounding the acute myocardial infarct site.DESIGN, TIME AND SETTING: The randomized, controlled, animal study was performed at the Laboratory of Neurobiology,Department of Human Anatomy and Neurobiology, Xiangya Medical College, Central South University from March 2007 to October 2008.MATERIALS: A total of 40 SPF grade Wistar rats were equally randomized into 4 groups, normal control, infarct model,central transplantation and peripheral transplantation groups. Embryonic stem cells-D3 (ES-D3) and Buffalo rat hepatocytas were supplied by Shanghai Cell Institute, Chinese Academy of Sciences.METHODS: Following resuscitation, ES-D3 cells at (2.0-5.0)×107/L were incubated in a flask, and induced to in vitro differentiate in conditioned medium containing Buffalo rat hepatocytes. Except normal control group, rat models of acute myocardial infarction were established by ligating left anterior descending coronary artery in the infarct model, central transplantation and peripheral transplantation groups. At 1 week following model induction, ES-D3 cells were labeled by BrdU for 1 day, and implanted at 1×109/L. Three sites were selected in the infarct site in the central transplantation group. 10 μ L cell suspension (104 cells) was implanted in the ventricular wall through each site. In the peripheral transplantation group, an equal volume of cell suspension was separately implanted in three peripheral infarct sites by the same method.MAIN OUTCOME MEASURES: Results of immunohistochemistry and hemodynamics were measured.RESULTS: ES-D3 cells in buffalo rat hepatocyte conditioned medium presented regular colony-shaped. At 8 days following differentiation, some embryo proper had spontaneous rhythmic contraction, showed positive reaction of cardiac troponin T after immunostaining. Under the electron microscope, myotube and muscle fiber appeared, which verified the differentiation of cardiomyocytes. Cells were positive for BrdU in the peripheral transplantation group, but negative in the central transplantation group. Cells were also positive for cardiac troponin T. 4 weeks following transplantation, left ventricular systolic pressure,minimum/maximum rate of ventricular pressure (±dp/dtmax) were significantly reduced (P ＜ 0.01), but left ventricular end diastolic pressure was significantly increased (P ＜ 0.01), left ventricular mass and left ventricular mass index were significantly increased (P ＜ 0.01 ) in the infarct model group compared with the normal control group. Compared with the infarct model group, no significant changes in hemodynamics indices were found in the central transplantation group (P ＞ 0.05); left ventricular systolic pressure, ±dp/dtmax were significantly increased (P ＜ 0.01), left ventricular end diastolic pressure was significantly decreased (P ＜ 0.01 ), left ventricular mass, left ventricular mass index and infarct area were significantly reduced(P ＜ 0.01) in the peripheral transplantation group.