| It is considered that subgranular zone and subventricular zone are the two major regions, which maintain neurogenesis in the adult mammalian brain. Only a small number of neural stem/progenitor cells can through proliferation, differentiation, migration and finally integrate into existing neural pathways to play a functional role as a newborn neuron.Environmental enrichment has been widely used as an intervention in adult neurogenesis recently. It is effective in promoting the proliferation of neural stem/progenitor cells in adult brain and improve the survival rate of newborn neurons. Different experimental purposes differ the requirements of the environmental intervention time, from two weeks to a year or two, or even longer, usually one to two months’ treatments are efficient. Environmental enrichment stimuli can be divided into odor-enriched and non-odor-enriched stimuli according to two specific target regions (SGZ and SVZ). The studies found that non-odor-enriched environment does not cause changes of neurogenesis in SVZ.Weaning mice, which are housed in the enriched environment, show increased hippocampal neural progenitor cell proliferation. Meanwhile, calmodulin in hippocampus and the phosphorylation of cAMP response element binding protein (CREB) expression also significantly increase. Those suggest that calmodulin expression may play an important role in the enriched environment-mediated neurogenesis. Calcium/calmodulin-dependent protein kinase Ⅱ (CaMKⅡ) is a member of Ca2+/CaM-regulated protein family. It has4subtypes:alpha, beta, gama and delta. Alpha and beta subtypes are abundant in nerve tissue, i.e. alpha subtype accounts for2%of the total protein in hippocampus. It is reported that difficiency of alpha-CaMKII may affect the development of dentate gyrus. Adult neural progenitor cell proliferation activity has increased, but eventually the newborn cell survival rate has decreased.The above background prompts the link among environmental enrichment, adult neurogenesis and alpha-CaMKII protein. Another, behavior-based detection of animal models are mostly male. Possibly the impact of gender difference on environmental enrichment would be ignored.Therefore, in this thesis,3-to-4-month male and female C57BL/6mice (B6), and forebrain-specific alpha-CaMKII protein overexpressed transgenic mice (alpha-CaMKII-F89G) were used as models, housed in enriched evironment for a period of two weeks.The differences of their behavioral phenotypes were observed to explore the role of alpha-CaMKII in the neurogenesis-dependent activities, as well as the role of gender difference.In addition, this project has also successfully established a3-to-4-month C57BL/6mice’s adult neural progenitor cells culture system in vitro.The paper includes the following three parts:A. Environmental enrichment affects behavioral phenotypes of C57BL/6male and female mice.In this section, the intervention of two-week non-odor-enriched stimuli were used to observe the sex difference on behavioral phenotypes of B6mice, such as spontaneous activity, sensory-motor, anxiety, schizophrenia-like mood, hippocampus-dependent memory, and the impact of olfactory function.It was found that two-week non-odor environmental enrichment stimulation can increase the female and male basic activity, sensorimotor ability; enhance their sense of odor distinguish; did not affectschizophrenia-like behavior, working memory and contextual fear memory performances. Gender differences in the results are that environmental enrichment increased anxiety-like mood of female B6mice, but has no effect on male mice.B. Environmental enrichment affects behavioral phenotypes of alpha-CaMKII-F89G transgenic male and female mice.In this section, the intervention of two-week non-odor-enriched stimuli were used to observe the sex difference on behavioral phenotypes of alpha-CaMKII-F89G transgenic mice, such as spontaneous activity, sensory-motor, anxiety, schizophrenia-like symptoms, hippocampus-dependent memory, and the impact of olfactory function.It was found that two-week non-odor environmental enrichment stimulation can increase the female and male sensorimotor ability;did not affect depressed, schizophrenia-like behavior and contextual fear memory performances. Gender differences in the results are that environmental enrichment increased anxiety-like mood of female B6mice, but has no effect on male mice. Besides, environmental enrichment improved the basic activity of the male alpha-CaMKII-F89G mice, no effect on the female mice.C. Adult neural progenitor cells cultured in vitro and in vivo detectionIn this section, we successfully established anadult neural progenitor cells primary culture system. Neural stem/progenitor cell-specific antigen Nestin was tagged to identify neural progenitor cells. While, endogenous adult neural progenitor cells (SVZ and SGZ) were identified by the insertion of the cell proliferation marker BrdU.The results showed that adult neural progenitor cells in selective medium containing EGF/bFGF/supplement can be successfully carried out the primary and subculture, and were Nestin positive. On the other hand, injection of BrdU for4h made it successfully insert into the proliferative activated neural progenitor cells, which was detected by immunohistochemistry fluorescence. |
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